N-aroyl cyclic amine derivatives as orexin receptor antagonists

ABSTRACT

Disclosed are N-aroyl cyclic amine derivatives having the formula: 
     
       
         
         
             
             
         
       
     
     where the variables are as define herein, and their use as pharmaceuticals, specifically as orexin receptor antagonists.

This application is a divisional of application Ser. No. 10/481,133, filed Apr. 26, 2004, which is a 371 of International Application No. PCT/EP02/07009, filed 25 Jun. 2002.

This invention relates to N-aroyl cyclic amine derivatives and their use as pharmaceuticals.

Many medically significant biological processes are mediated by proteins participating in signal transduction pathways that involve G-proteins and/or second messengers.

Polypeptides and polynucleotides encoding the human 7-transmembrane G-protein coupled neuropeptide receptor, orexin-1 (HFGAN72), have been identified and are disclosed in EP-A-875565, EP-A-875566 and WO 96/34877. Polypeptides and polynucleotides encoding a second human orexin receptor, orexin-2 (HFGANP), have been identified and are disclosed in EP-A-893498.

Polypeptides and polynucleotides encoding polypeptides which are ligands for the orexin-1 receptor, e.g. orexin-A (Lig72A) are disclosed in EP-A-849361.

Orexin receptors are found in the mammalian host and may be responsible for many biological functions, including pathologies including, but not limited to, depression; anxiety; addictions; obsessive compulsive disorder; affective neurosis/disorder; depressive neurosis/disorder; anxiety neurosis; dysthymic disorder; behaviour disorder; mood disorder; sexual dysfunction; psychosexual dysfunction; sex disorder; sexual disorder; schizophrenia; manic depression; delerium; dementia; severe mental retardation and dyskinesias such as Huntington's disease and Gilles de la Tourett's syndrome; disturbed biological and circadian rhythms; feeding disorders, such as anorexia, bulimia, cachexia, and obesity; diabetes; appetite/taste disorders; vomiting/nausea; asthma; cancer; Parkinson's disease; Cushing's syndrome/disease; basophil adenoma; prolactinoma; hyperprolactinemia; hypopituitarism; hypophysis tumor/adenoma; hypothalamic diseases; Froehlich's syndrome; adrenohypophysis disease; hypophysis disease; hypophysis tumor/adenoma; pituitary growth hormone; adrenohypophysis hypofunction; adrenohypophysis hyperfunction; hypothalamic hypogonadism; Kallman's syndrome (anosmia, hyposmia); functional or psychogenic amenorrhea; hypopituitarism; hypothalamic hypothyroidism; hypothalamic-adrenal dysfunction; idiopathic hyperprolactinemia; hypothalamic disorders of growth hormone deficiency; idiopathic growth hormone deficiency; dwarfism; gigantism; acromegaly; and sleep disturbances associated with such diseases as neurological disorders, neuropathic pain and restless leg syndrome, heart and lung diseases; acute and congestive heart failure; hypotension; hypertension; urinary retention; osteoporosis; angina pectoris; myocardial infarction; ischaemic or haemorrhagic stroke; subarachnoid haemorrhage; head injury such as sub-arachnoid haemorrhage associated with traumatic head injury; ulcers; allergies; benign prostatic hypertrophy; chronic renal failure; renal disease; impaired glucose tolerance; migraine; hyperalgesia; pain; enhanced or exaggerated sensitivity to pain, such as hyperalgesia, causalgia and allodynia; acute pain; burn pain; atypical facial pain; neuropathic pain; back pain; complex regional pain syndromes I and II; arthritic pain; sports injury pain; pain related to infection, e.g. HIV, post-polio syndrome, and post-herpetic neuralgia; phantom limb pain; labour pain; cancer pain; post-chemotherapy pain; post-stroke pain; post-operative pain; neuralgia; nausea, vomiting; conditions associated with visceral pain including irritable bowel syndrome, migraine and angina; urinary bladder incontinence e.g. urge incontinence; tolerance to narcotics or withdrawal from narcotics; sleep disorders; sleep apnea; narcolepsy; insomnia; parasomnia; jet-lag syndrome; and neurodegenerative disorders, which includes nosological entities such as disinhibition-dementia-parkinsonism-amyotrophy complex; pallido-ponto-nigral degeneration, epilepsy, and seizure disorders.

Experiments have shown that central administration of the ligand orexin-A (described in more detail below) stimulated food intake in freely-feeding rats during a 4 hour time period. This increase was approximately four-fold over control rats receiving vehicle. These data suggest that orexin-A may be an endogenous regulator of appetite. Therefore, antagonists of its receptor may be useful in the treatment of obesity and diabetes, see Cell, 1998, 92, 573-585.

There is a significant incidence of obesity in westernised societies. According to WHO definitions a mean of 35% of subjects in 39 studies were overweight and a further 22% clinically obese. It has been estimated that 5.7% of all healthcare costs in the USA are a consequence of obesity. About 85% of Type 2 diabetics are obese, and diet and exercise are of value in all diabetics. The incidence of diagnosed diabetes in westernised countries is typically 5% and there are estimated to be an equal number undiagnosed. The incidence of both diseases is rising, demonstrating the inadequacy of current treatments which may be either ineffective or have toxicity risks including cardiovascular effects. Treatment of diabetes with sulfonylureas or insulin can cause hypoglycaemia, whilst metformin causes GI side-effects. No drug treatment for Type 2 diabetes has been shown to reduce the long-term complications of the disease. Insulin sensitisers will be useful for many diabetics, however they do not have an anti-obesity effect.

Rat sleep/EEG studies have also shown that central administration of orexin-A, an agonist of the orexin receptors, causes a dose-related increase in arousal, largely at the expense of a reduction in paradoxical sleep and slow wave sleep 2, when administered at the onset of the normal sleep period. Therefore antagonists of its receptor may be useful in the treatment of sleep disorders including insomnia.

The present invention provides N-aroyl cyclic amine derivatives which are non-peptide antagonists of human orexin receptors, in particular orexin-1 receptors. In particular, these compounds are of potential use in the treatment of obesity, including obesity observed in Type 2 (non-insulin-dependent) diabetes patients, and/or sleep disorders Additionally these compounds are useful in stroke, particularly ischemic or haemorrhagic stroke, and/or blocking the emetic response i.e. the compounds are useful in the treatment of nausea and vomiting.

International Patent Applications WO99/09024, WO99/58533, WO00/47577 and WO00/47580 disclose phenyl urea derivatives and WO00/47576 discloses quinolinyl cinnamide derivatives as orexin receptor antagonists. (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(1H-indol-3-ylmethyl)piperazine is disclosed in EP899270 as a starting material in the preparation of compounds useful for therapy of functional and inflammatory disorders of the gastrointestinal tract. The compound is also disclosed as Example 6 in EP655442. EP655442 describes piperizine derivatives useful as Tachykinin antagonists. 1-Benzoyl-2-[(1H-indol-3-yl)methyl]piperazine is also disclosed therein.

(2R)-1-(3,5-dichlorobenzoyl)-2-[(1H-indol-3-yl)methyl]piperazine and (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-[1H-indol-3-yl)methyl]piperazine are used as starting materials/intermediates in WO9857954.

(2R)-2-[1H-indol-3-yl)methyl]-1-[3-methoxy-5-trifluoromethyl)benzoyl]piperazine, is disclosed as a prepared by preparation 42 in WO00/35915.

According to the invention there is provided a compound of formula (I):

wherein:

X represents a bond, oxygen, NR³ or a group (CH₂)_(n), wherein n represents 1, 2 or 3;

Y represents CH₂, CO, CH(OH), or CH₂CH(OH);

Het is an optionally substituted bicyclic heteroaryl group containing up to 4 heteroatoms selected from N, O and S;

Ar² represents an optionally substituted phenyl or a 5- or 6-membered heterocyclyl group containing up to 3 heteroatoms selected from N, O and S, wherein the phenyl or heterocyclyl group is substituted by R¹ and further optional substituents; or Ar² represents an optionally substituted bicyclic aromatic or bicyclic heteroaromatic group containing up to 3 heteroatoms selected from N, O and S;

R¹ represents hydrogen, optionally substituted(C₁₋₄)alkoxy, halo, cyano, optionally substituted(C₁₋₆)alkyl, optionally substituted phenyl, or an optionally substituted 5- or 6-membered heterocyclyl group containing up to 4 heteroatoms selected from N, O and S;

R³ represents hydrogen or an optionally substituent (C₁₋₄)alkyl other than when Het is indolyl where R³ represents hydrogen or (C₁₋₄) alkyl;

or a pharmaceutically acceptable salt thereof with the proviso that;

when X is NH, Y is CH₂ and Het is indolyl, Ar² is not 3,5-bis(trifluoromethyl)phenyl;

or the compound is not

-   (2R)-1-(3,5-dichlorobenzoyl)-2-[(1H-indol-3-yl)methyl]piperazine; -   (2R)-2-[1H-indol-3-yl)methyl]-1-[3-methoxy-5-trifluoromethyl)benzoyl]piperazine;     or -   1-benzolyl-2-[1H-indol-3-yl)methyl]piperazine.

Preferably where Ar² represents phenyl or a 5- or 6-membered heterocyclyl group containing up to 3 heteroatoms selected from N, O and S, the R¹ group is situated adjacent to the point of attachment to the amide carbonyl.

X is preferably a bond, oxygen or CH₂, NH or NMe, more preferably CH₂, NH or NMe, most preferably CH₂.

Alternatively X is preferably a bond, oxygen or (CH₂)n wherein n is 1 or 2.

Y is preferably CH₂.

Preferably R³ is hydrogen or a (C₁₋₄)alkyl.

Het may have up to 5, preferably 1, 2 or 3 optional substituents.

Examples of when Het is an optionally substituted bicyclic heteroaryl group are quinoxalinyl, quinazolinyl, pyridopyrazinyl, benzoxazolyl, benzothienyl, benzofuranyl, benzimidazolyl, naphthyridinyl or benzothiazolyl. Additionally Het may be indolyl, triazolopyridinyl, furopyridinyl, pyridopyrimidinyl, isoquinolinyl or quinolinyl. Furthermore Het can be oxazolylpyridinyl or tetrahydrobenzimidazolyl, tetrahydrobenzofuranyl, or tetrahydrotriazolopyridinyl.

Preferably Het is benzofuranyl, benzoxazolyl, benzimidazolyl, furopyridinyl, benzothiazolyl, indolyl, benzothienyl, triazolopyridinyl, quinolinyl and tetrahydrotriazolopyryidinyl, more preferably benzimidazolyl, benzofuranyl, benzoxazolyl, even more preferably benzofuranyl or benzimidazolyl.

When Ar² is a 5- or 6-membered heteroaryl group containing up to 3 heteroatoms selected from N, O and S, it may be furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, triazinyl, pyridazinyl, pyridinyl, pyrimidinyl, isothiazolyl, isoxazolyl, pyrazinyl or pyrazolyl.

More specifically, examples of Ar² are thiazolyl, pyrazolyl, triazolyl, pyridazinyl, oxazolyl, pyridinyl, pyrimidinyl, isoxazolyl and thienyl.

When R¹ is a 5- or 6-membered heterocyclyl group containing up to 4 heteroatoms selected from N, O and S, it may be furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, pyridinyl, triazolyl, triazinyl, pyridazinyl, pyrimidinyl, isothiazolyl, isoxazolyl, pyrazinyl or pyrazolyl. Additional heterocyclyl groups can be morpholinyl, piperazinyl and thiomorpholinyl. Furthermore it can be tetrazolyl, piperidinyl or pyrrolidinyl.

Preferably when R¹ is a 5- or 6-membered heterocyclyl group containing up to 4 heteroatoms selected from N, O and S, it may be oxadiazolyl, pyridinyl, pyrimidinyl, morpholinyl pyrazolyl or pyrrolyl.

Examples of where Ar² represents an optionally substituted bicyclic aromatic or bicyclic heteroaromatic include naphthyl, quinolinyl, napththyridinyl, benzofuranyl, benzimidazolyl, quinoxalinyl or quinazolinyl. Additionally Ar² may be isoquinolinyl or benzoxazolyl. Furthermore it can benzotriazolyl, benzothienyl, indolyl, benzothiazolyl, or benzothiadiazolyl.

Preferably Ar² represents optionally substituted phenyl, pyridinyl, thiazolyl, pyrazolyl, pyridazinyl, thienyl, naphthyl, triazolyl, isoxazolyl, quinolinyl, or isoquinolinyl.

More preferably Ar² represents optionally substituted phenyl, pyridinyl, thiazolyl, pyrazolyl, thienyl, triazolyl, quinolinyl, or isoquinolinyl.

Even more preferably Ar² represents optionally substituted phenyl, pyridinyl, thiazolyl, pyrazolyl, thienyl, or 1,2,3-triazolyl.

Alternatively R¹ represents hydrogen, optionally substituted(C₁₋₄)alkoxy, halo, optionally substituted(C₁₋₆)alkyl, optionally substituted phenyl, or an optionally substituted 5- or 6-membered heterocyclyl group containing up to 3 heteroatoms selected from N, O and S.

Preferably R¹ represents optionally substituted(C₁₋₄)alkoxy, halo, optionally substituted(C₁₋₆)alkyl, optionally substituted phenyl, or an optionally substituted 5- or 6-membered heterocyclyl group containing up to 3 heteroatoms selected from N, O and S.

Even more preferably R¹ represents an optionally substituted phenyl, pyridinyl, pyrazolyl pyrimidinyl or oxadiazolyl group.

Optional substituents for the groups Het, Ar², R¹ and R³ include halogen, hydroxy, oxo, cyano, nitro, (C₁₋₄)alkyl, (C₁₋₄)alkoxy, hydroxy(C₁₋₄)alkyl, hydroxy(C₁₋₄)alkoxy, halo(C₁₋₄)alkyl, halo(C₁₋₄)alkoxy, aryl(C₁₋₄)alkoxy, (C₁₋₄)alkylthio, hydroxy(C₁₋₄)alkyl, (C₁₋₄)alkoxy(C₁₋₄)alkyl, (C₃₋₆)cycloalkyl(C₁₋₄)alkoxy, (C₁₋₄)alkanoyl, (C₁₋₄)alkoxycarbonyl, (C₁₋₄)alkylsulfonyl, (C₁₋₄)alkylsulfonyloxy, (C₁₋₄)alkylsulfonyl(C₁₋₄)alkyl, arylsulfonyl, arylsulfonyloxy, arylsulfonyl(C₁₋₄)alkyl, (C₁₋₄)alkylsulfonamido, (C₁₋₄)alkylamido, (C₁₋₄)alkylsulfonamido(C₁₋₄)alkyl, (C₁₋₄)alkylamido(C₁₋₄)alkyl, arylsulfonamido, arylcarboxamido, arylsulfonamido(C₁₋₄)alkyl, arylcarboxamido(C₁₋₄)alkyl, aroyl, aroyl(C₁₋₄)alkyl, or aryl(C₁₋₄)alkanoyl group; a group R^(a)R^(b)N—, R^(a)OCO(CH₂)_(r), R^(a)CON(R^(a))(CH₂)_(r), R^(a)R^(b)NCO(CH₂)_(r), R^(a)R^(b)NSO₂(CH₂)_(r) or R^(a)SO₂NR^(b)(CH₂)_(r) where each of R^(a) and R^(b) independently represents a hydrogen atom or a (C₁₋₄)alkyl group or where appropriate R^(a)R^(b) forms part of a (C₃₋₆)azacycloalkane or (C₃₋₆)(2-oxo)azacycloalkane ring and r represents zero or an integer from 1 to 4. Additional substituents are (C₁₋₄)acyl, aryl, aryl(C₁₋₄)alkyl, (C₁₋₄)alkylamino(C₁₋₄)alkyl, R^(a)R^(b)N(CH₂)n-, R^(a)R^(b)N(CH₂)nO—, wherein n represents an integer from 1 to 4. Additionally when the substituent is R^(a)R^(b)N(CH₂)n- or R^(a)R^(b)N(CH₂)nO, R^(a) with at least one CH₂ of the (CH₂)n portion of the group form a (C₃₋₆)azacycloalkane and R^(b) represents hydrogen, a (C₁₋₄)alkyl group or with the nitrogen to which it is attached forms a second (C₃₋₆)azacycloalkane fused to the first (C₃₋₆)azacycloalkane.

Preferred optional substituents for Ar² are halogen, cyano, (C₁₋₄)alkyl, hydroxy(C₁₋₄)alkyl, (C₁₋₄)alkoxy(C₁₋₄)alkyl, R^(a)R^(b)N(CH₂)n or R^(a)R^(b)N, more preferably halogen, cyano and (C₁₋₄)alkyl. Additional substituents are (C₁₋₄)acyl, R^(a)R^(b)N(CH₂)nO, (C₁₋₄)alkoxy, phenyl, and (C₁₋₄)alkylamido.

More preferred substituents for Ar² are (C₁₋₄)alkyl, hydroxy(C₁₋₄)alkyl, R^(a)R^(b)N, (C₁₋₄)alkoxy, R^(a)R^(b)N(CH₂)n, (C₁₋₄)acyl, and (C₁₋₄)alkylamido.

Preferred optional substituents for Het are halogen, cyano, (C₁₋₄)alkyl, hydroxy(C₁₋₄)alkyl, (C₁₋₄)acyl, (C₁₋₄)alkoxy(C₁₋₄)alkyl, R^(a)R^(b)NCO(CH₂)_(r), R^(a)R^(b)N(CH₂)_(n), R^(a)R^(b)N(CH₂)nO or R^(a)R^(b)N. Additional optional substituents are (C₁₋₄)alkoxy or CF₃.

More preferred substituents for Het are halogen, R^(a)R^(b)NCO(CH₂)_(r), cyano, (C₁₋₄)alkoxy, (C₁₋₄)alkyl, R^(a)R^(b)N(CH₂)n, hydroxy(C₁₋₄)alkyl, (C₁₋₄)acyl or (C₁₋₄)alkoxy(C₁₋₄)alkyl.

Preferred optional substituents for R¹ are halogen, (C₁₋₄)alkoxy(C₁₋₄)alkyl, R^(a)R^(b)N, R^(a)R^(b)N(CH₂)nO or R^(a)R^(b)N(CH₂)n. Additional optional substituents are (C₁₋₄)alkyl, (C₁₋₄)alkoxy and (C₁₋₄)acyl.

More preferred substituents for R¹ are halogen, R^(a)R^(b)N(CH₂)nO, (C₁₋₄)alkyl, and (C₁₋₄)alkoxy.

Preferred optional substituents for R³ may be selected from halogen, hydroxy, cyano, (C₁₋₄)alkoxy, R^(a)R^(b)N(CH₂)nO or R^(a)R^(b)N.

In the groups Het and Ar², substituents positioned ortho to one another may be linked to form a ring.

Illustrative compounds of formula (I) can be selected from:

1 (RS)-2-(2-Benzofuranylmethyl)-1-((5-(4-fluorophenyl)-2-methyl- thiazol-4-yl)-carbonyl)-piperidine 2 (RS)-1-(2-Benzooxazol-2-ylmethyl-piperidin-1-yl)-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 3 (RS)-1-(2-Benzooxazol-2-ylmethyl-piperidin-1-yl)-1-[2-(3-methyl- [1,2,4]oxadiazol-5-yl)-phenyl]-methanone and pharmaceutical acceptable salts thereof. Additional compounds of formula (I) can be selected from:

4 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[4-(4-fluoro-phenyl)-1- methyl-1-H-pyrazol-3-yl]-methane 5 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 6 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-(5-pyridin- 2-yl-thiazol-4-yl)-methanone 7 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-quinolin-4- yl-methanone 8 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-quinolin-5- yl-methanone 9 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-(2-methoxy- pyridin-3-yl)-methanone 10 (RS)-1-[2-Dimethylamino-5-(4-fluoro-phenyl)-thiazol-4-yl]-1-[2-(5-fluoro- benzofuran-2-ylmethyl)-piperidin-1-yl]-methanone 11 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-(2- morpholin-4-yl-phenyl)-methanone 12 (RS)-1-[2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-(2- trifluoromethoxy-phenyl)-methanone 13 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[2-(2-dimethylamino- ethoxy)-phenyl]-methanone 14 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-quinolin-8-yl-methanone 15 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-(2-pyrimidin-2-yl- phenyl)-methanone 16 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[5-(4-fluoro-phenyl)- 2H-[1,2,3]triazol-4-yl]-methanone 17 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[4-(4-fluoro-phenyl)- 1H-pyrazol-3-yl]-methanone 18 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[5-(4-fluoro-phenyl)-2- hydroxymethyl-thiazol-4-yl]-methanone 19 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-isoquinolin-8-yl-methanone 20 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-isoquinolin-5-yl-methanone 21 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-{5-[3-(3- dimethylamino-propoxy)-phenyl]-2-methyl-thiazol-4-yl}-methanone 22 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-{5-[3-(4- dimethylamino-butoxy)-phenyl]-2-methyl-thiazol-4-yl}-methanone 23 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-furo[2,3- b]pyridin-2-ylmethyl-piperidin-1-yl)-methanone 24 (RS)-1-[4-(4-Fluoro-phenyl)-1-methyl-1H-pyrazole-3-yl]-(2-furo[2,3- b]pyridin-2-ylmethyl-piperidin-1-yl)methanone 25 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-quinolin-2- ylmethyl-piperidin-1-yl)-methanone 26 (RS)-1-Benzofuran-2-yl-1-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4- yl]-methanoyl}-piperidin-2-yl)-methanone 27 (RS)-1-[2-(1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 28 (RS)-1-[2-(5-Chloro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 29 (RS)-1-[2-(5-Fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 30 (RS)-1-[2-(5-Chloro-6-fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1- yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 31 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-[2-(4-methyl-1H- benzoimidazol-2-ylmethyl)-piperidin-1-yl]-methanone 32 (RS)-1-[2-(4,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 33 (RS)-1-[2-(4-Dimethylaminomethyl-1H-benzoimidazol-2-ylmethyl)- piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 34 (RS)-1-[2-(5-Bromo-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 35 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 36 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 37 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone 38 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone 39 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone 40 (RS)-1-[2-(5-Methoxy-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 41 (RS)-1-[2-(6,7-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-methyl-5-phenyl-thiazol-4-yl)-methanone 42 (RS)-1-[2-(6,7-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone 43 (RS)-1-[2-(6,7-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [4-(4-fluoro-phenyl)-1H-pyrazol-3-yl]-methanone 44 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- {5-[3-(2-dimethylamino-ethoxy)-phenyl]-2-methyl-thiazol-4-yl}-methanone 45 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(2-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 46 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(3-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 47 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-trifluoromethoxy-phenyl)-methanone 48 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-ethoxy-phenyl)-methanone 49 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2,6-dimethoxy-phenyl)-methanone 50 (RS)-1-[2-(6,7-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-pyrazol-1-yl-phenyl)-methanone 51 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [4-(4-fluoro-phenyl)-1H-pyrazol-3-yl]-methanone 52 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [2-(3-methyl-[1,2,4]oxadiazol-5-yl)-phenyl]-methanone 53 (RS)-1-[2-(Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[1- (2-dimethylamino-ethyl)-4-(4-fluoro-phenyl)-1H-pyrazol-3-yl]-methanone 54 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-2H-[1,2,3]triazol-4-yl]-methanone 55 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- {2-[3-(3-dimethylamino-propoxy)-phenyl]-thiophen-3-yl}-methanone 56 (RS)-1-[2-(5,6-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)- piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 57 1-[(S)-2-(1H-Benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 58 1-[(S)-2-(5,6-Difluoro-1H-Benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 59 1-[(S)-2-(5,6-Difluoro-1H-Benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1- [4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]methanone 60 (RS)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-1-[5-(4-fluorophenyl)-2- methylthiazol-4-yl]-methanone 61 (RS)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-1-[4-(4-fluorophenyl)-1- methyl-1-H-pyrazol-3-yl]-methanone 62 (RS)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-1-[2-(3-methyl- [1,2,4]oxadiazol-5-yl)phenyl]-methanone 63 (RS)-1-[5-(4-Fluorophenyl)-2-methylthiazol-4-yl]-1-[2-(5,6,7,8-tetrahydro- [1,2,4]-triazolo[1,5-a]pyridin-2-ylmethyl)-piperidin-1-yl]-methanone 64 (RS)-1-[5-(4-Fluorophenyl)-2-methylthiazol-4-yl]-1-(2-[1,2,4]triazolo[1,5- a]pyridin-2-ylmethylpiperidin-1-yl)-methanone 65 1-[(RS)-2-((RS)-2-Benzofuran-2-yl-2-hydroxy-ethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone (as separate diastereoisomers) 66 (RS)-1-[2-(4-Bromo-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluorophenyl)-2-methylthiazol-4-yl]methanone 67 (RS)-1-[2-(4-Cyano-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluorophenyl)-2-methylthiazol-4-yl]methanone 68 (RS)-1-[2-(4-Acetyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluorophenyl)-2-methylthiazol-4-yl]methanone 69 (RS)-2-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}- piperidin-2-ylmethyl)-1H-benzoimidazole-5-carbonitrile 70 (RS)-1-[2-(5,6-Difluoro-1-propyl-1H-benzoimidazol-2-ylmethyl)-piperidin- 1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 71 (RS)-1-{2-[5,6-Difluoro-1-(2-methoxy-ethyl)-1H-benzoimidazol-2- ylmethyl]-piperidin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 72 (RS)-1-{2-[1-(2-Dimethylamino-ethyl)-5,6-difluoro-1H-benzoimidazol-2- ylmethyl]-piperidin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 73 (RS)-1-{2-[5,6-difluoro-1-(2-hydroxy-ethyl)-1H-benzoimidazol-2- ylmethyl]-piperidin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 74 (RS)-1-[2-(6,7-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)- piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone 75 (RS)-1-[2-(4,5-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)- piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone 76 (RS)-2-(1-{1-[5-(4-Fluorophenyl)-2-methyl-thiazol-4-yl]-methanoyl}- piperidin-2-ylmethyl)-benzofuran-3-carboxylic acid amide 77 (RS)-2-(1-{1-[4-(4-Fluorophenyl)-1-methyl-1H-pyrazol-3-yl]-methanoyl}- piperidin-2-ylmethyl)-benzofuran-3-carboxylic acid amide 78 (RS)-1-[3-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-morpholin-4-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 79 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-furo[3,2-b]- pyridin-2-ylmethyl-piperidin-1-yl)methanone 80 (RS)-1-[4-(4-Fluoro-phenyl)-1-methyl-1H-pyrazole-3-yl)-(2-furo[3,2- b]pyridin-2-ylmethyl-piperidin-1-yl)methanone 81 (RS)-1-[2-(3-Bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4- fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 82 (RS)-2-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}- piperidin-2-ylmethyl)-benzofuran-3-carbonitrile 83 (RS)-1-[2-(5-Fluorobenzofuran-2-ylmethyl)-4-methylpiperazin-1-yl]-1-[5- (4-fluorophenyl)-2-methythiazol-4-yl]methanone 84 (RS)-1-(2-Benzofuran-2-ylmethyl-4-methyl-piperazin-1-yl)-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl)]-methanone 85 (RS)-1-(2-Benzofuran-2-ylmethyl-piperazin-1-yl)-1-[5-(4-fluorophenyl)-2- methyl-thiazol-4-yl]-methanone 86 1-{(RS)-2-[(RS)-1-(5-Fluoro-benzofurany-2-yl)-1-hydroxy-methyl]-4- methyl-piperazin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 87 1-{(RS)-2-[(RS)-1-(5-Fluoro-benzofurany-2-yl)-1-hydroxy-methyl]-4- methyl-piperazin-1-yl}-1-(2-trifluoromethoxy-phenyl)-methanone 88 (RS)-1-[2-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}- piperidin-2-ylmethyl)-benzofuran-3-yl]-ethanone 89 (R)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoneand(S)-1-[2-(5,6- Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone and pharmaceutically acceptable salts thereof. Further compounds of formula (I) can be selected from

90 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[5-(4-methoxy- phenyl)-2-methyl-thiazol-4-yl]-methanone 91 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-{5-[3-(2- dimethylamino-ethoxy)-phenyl]-2-methyl-thiazol-4-yl}-methanone 92 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (5-methyl-3-phenyl-isoxazol-4-yl)-methanone 93 1-[3-(2,6-Dichloro-phenyl)-5-methyl-isoxazol-4-yl]-1-[2-(4,5-difluoro-1H- benzoimidazol-2-ylmethyl)-piperidin-1-yl]-methanone 94 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [4-(4-fluoro-phenyl)-2-methyl-2H-pyrazol-3-yl]-methanone 95 (RS)-1-[3-(2-Chloro-6-fluoro-phenyl)-5-methyl-isoxazol-4-yl]-1-[2-(4,5- difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-methanone 96 (RS)-1-[3-(2-Chloro-phenyl)-5-methyl-isoxazol-4-yl]-1-[2-(4,5-difluoro- 1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-methanone 97 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-propoxy-phenyl)-methanone 98 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-isopropoxy-phenyl)-methanone 99 (RS)-1-(2-Benzyloxy-phenyl)-1-[2-(4,5-difluoro-1H-benzoimidazol-2- ylmethyl)-piperidin-1-yl]-methanone 100 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-ethoxy-6-methoxy-phenyl)-methanone 101 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-ethoxy-6-methyl-phenyl)-methanone 102 (RS)-1-(2,6-Diethoxy-phenyl)-1-[2-(4,5-difluoro-1H-benzoimidazol-2- ylmethyl)-piperidin-1-yl]-methanone 103 1-(3-{1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]- methanoyl}-4-ethoxy-phenyl)-ethanone 104 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-ethoxy-naphthalen-1-yl)-methanone 105 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- (2-pyridin-2-yl-phenyl)-methanone 106 1-[2-(6,7-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-(2- pyrrol-1-yl-phenyl)-methanone 107 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- {5-[3-(3-dimethylamino-propoxy)-phenyl]-2-methyl-thiazol-4-yl}-methanone 108 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- {5-[3-(4-dimethylamino-butoxy)-phenyl]-2-methyl-thiazol-4-yl}-methanone 109 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methoxy-thiazol-4-yl]-methanone 110 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [2-ethyl-5-(4-fluoro-phenyl)-thiazol-4-yl]-methanone 111 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(2-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 112 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1- [5-(3-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 113 (RS)-1-[2-(4-Fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 114 (RS)-1-[2-(4-Fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[4- (4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone 115 (RS)-1-[2-(4-Fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[4- (4-fluoro-phenyl)-1H-pyrazol-3-yl]-methanone 116 (RS)-1-[2-(4-Fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[4- (4-fluoro-phenyl)-2-methyl-2H-pyrazol-3-yl]-methanone 117 (RS)-1-(2-Ethoxy-phenyl)-1-[2-(4-fluoro-1H-benzoimidazol-2-ylmethyl)- piperidin-1-yl]-methanone 118 (RS)-1-[2-(4-Fluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone 119 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-{2-[4-(1-hydroxy- ethyl)-1H-benzoimidazol-2-ylmethyl]-piperidin-1-yl}-methanone 120 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[5-(4-chloro-phenyl)- 2-methyl-thiazol-4-yl]-methanone 121 (RS)-1-[2-(3-Chloro-furo[3,2-b]pyridin-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 122 (RS)-1-[2-(5,6-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)- piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone 123 (RS)-1-[2-(5-Chloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1- [5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 124 (RS)-1-[2-(5-Chloro-benzofuran-2-ylmethyl)-piperazin-1-yl]-1-[5-(4- fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 125 (RS)-1-[2-(5,7-Dichloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]- 1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 126 (RS)-1-[2-(5,7-Dichloro-benzofuran-2-ylmethyl)-piperazin-1-yl]-1-[5-(4- fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 127 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-[2-(1H-indol-2- ylmethyl)-piperidin-1-yl]-methanone 128 (RS)-5-[1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-methanoyl]-4H- benzo[1,4]oxazin-3-one 129 (RS)-1-[2-(5-Bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4- fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 130 (RS)-1-[2-(5-Cyano-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 131 (RS)-1-[2-(4-Bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4- fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 132 (RS)-1-[2-(4-Cyano-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 133 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-[2-(3-methyl- benzofuran-2-ylmethyl)-piperidin-1-yl]-methanone 134 (RS)-1-[2-(4-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 135 (RS)-1-[2-(4-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[4-(4-fluoro- phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone 136 (RS)-1-[2-(4,6-Dichloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]- 1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 137 (RS)-1-[2-(4,6-Dichloro-benzofuran-2-ylmethyl)-piperazin-1-yl]-1-[5-(4- fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone 138 (RS)-1-(2-Benzofuran-2-ylmethyl-pyrrolidin-1-yl)-1-[5-(4-fluoro-phenyl)- 2-methyl-thiazol-4-yl]-methanone 139 (RS)-1-(2-Benzofuran-2-ylmethyl-pyrrolidin-1-yl)-1-[4-(4-fluoro-phenyl)- 1-methyl-1H-pyrazol-3-yl]-methanone 140 (RS)-1-(2-Benzo[b] thiophen-2-ylmethyl-piperidin-1-yl)-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone 141 (RS)-1-(2-Benzo[b]thiophen-2-ylmethyl-piperidin-1-yl)-1-[4-(4-fluoro- phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone 142 (RS)-1-(2-Benzo[b]thiophen-2-ylmethyl-piperidin-1-yl)-1-quinolin-8-yl-methanone 143 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-(2-methyl-5-phenyl- thiazol-4-yl)-methanone 144 1-[(S)-2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1- [5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone 145 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[2-(3-methyl- [1,2,4]oxadiazol-5-yl)-phenyl]-methanone 146 (R)-1-[2-(4,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5- (4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone and (S)-1-[2-(4,6- Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro- phenyl)-2-methyl-thiazol-4-yl]-methanone and pharmaceutically acceptable salts thereof.

When a halogen atom is present in the compound of formula (I) it may be fluorine, chlorine, bromine or iodine.

When the compound of formula (I) contains an alkyl group, whether alone or forming part of a larger group, e.g. alkoxy or alkylthio, the alkyl group may be straight chain, branched or cyclic, or combinations thereof, it is preferably methyl or ethyl.

When used herein the term aryl means a 5- to 6-membered ring for example phenyl, or a 7- to 12 membered bicyclic ring system where at least one of the rings is aromatic for example naphthyl.

When used herein the term bicyclic hetero aryl means a 7- to 12 membered bicyclic ring system where at least one of the rings is aromatic for example benzimidazoyl, or tetrahydrobenzimidazolyl.

It will be appreciated that compounds of formula (I) may exist as R or S enantiomers. The present invention includes within its scope all such isomers, including mixtures. Where additional chiral centres are present in compounds of formula (I), the present invention includes within its scope all possible diastereoisomers, including mixtures thereof. The different isomeric forms may be separated or resolved one from the other by conventional methods, or any given isomer may be obtained by conventional synthetic methods or by stereospecific or asymmetric syntheses.

It will be understood that the invention includes pharmaceutically acceptable derivatives of compounds of formula (I) and that these are included within the scope of the invention.

Particular compounds according to the invention include those mentioned in the examples and their pharmaceutically acceptable derivatives.

As used herein “pharmaceutically acceptable derivative” includes any pharmaceutically acceptable salt, ester or salt of such ester of a compound of formula (I) which, upon administration to the recipient is capable of providing (directly or indirectly) a compound of formula (I) or an active metabolite or residue thereof.

It will be appreciated that for use in medicine the salts of the compounds of formula (I) should be pharmaceutically acceptable. Suitable pharmaceutically acceptable salts will be apparent to those skilled in the art and include acid addition salts formed with inorganic acids e.g. hydrochloric, hydrobromic, sulphuric, nitric or phosphoric acid; and organic acids e.g. succinic, maleic, acetic, fumaric, citric, tartaric, benzoic, p-toluenesulfonic, methanesulfonic or naphthalenesulfonic acid. Other salts e.g. oxalates, may be used, for example in the isolation of compounds of formula (I) and are included within the scope of this invention. Also included within the scope of the invention are solvates and hydrates of compounds of formula (I).

Certain of the compounds of formula (I) may form acid addition salts with one or more equivalents of the acid. The present invention includes within its scope all possible stoichiometric and non-stoichiometric forms.

Since the compounds of formula (I) are intended for use in pharmaceutical compositions it will readily be understood that they are each preferably provided in substantially pure form, for example at least 60% pure, more suitably at least 75% pure and preferably at least 85%, especially at least 98% pure (% are on a weight for weight basis). Impure preparations of the compounds may be used for preparing the more pure forms used in the pharmaceutical compositions.

According to a further feature of the invention there is provided a process for the preparation of compounds of formula (I) and salts thereof. The following schemes detail some synthetic routes to compounds of the invention.

wherein, X, Het, and Ar² are as defined for compounds of formula (I), P is a protecting group and M is a metal for example lithium.

Examples of suitable leaving groups L₁ include halogen, OC(═O)alkyl and OC(═O)O-alkyl. The transformation (II) to (I) may be carried out in an inert solvent such as dichloromethane, in the presence of a base such as triethylamine. Alternatively this step may be carried out when L¹ represents hydroxy, in which case reaction with (II) takes place in an inert solvent such as dichloromethane in the presence of a diimide reagent such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and an activator such as 1-hydroxybenzotriazole.

Examples of protecting groups P include t-butyloxycarbonyl, trifluoroacetyl and benzyloxycarbonyl. Deprotection conditions are respectively, acid (e.g. trifluoroacetic acid in dichloromethane), base (e.g. sodium hydroxide in a solvent such as aqueous methanol) and catalytic hydrogenolysis in an inert solvent (e.g using palladium on charcoal in a lower alcohol or ethyl acetate).

Compounds of formula (V) are known in the literature or can be prepared by known methods.

wherein, X, and Ar² are as defined for compounds of formula (I), Z is S, or O, and P is a protecting group.

wherein, X, and Ar² are as defined for compounds of formula (I) and P is a protecting group.

Examples of protecting groups P include t-butyloxycarbonyl, trifluoroacetyl and benzyloxycarbonyl. Deprotection conditions are respectively, acid (e.g. trifluoroacetic acid in dichloromethane), base (e.g. sodium hydroxide in a solvent such as aqueous methanol) and catalytic hydrogenolysis in an inert solvent (e.g using palladium on charcoal in a lower alcohol or ethyl acetate).

The transformation of A to B can be carried out at elevated temperature in the absence of solvent or in the presence of an acid such as sulfuric acid or polyphosphoric acid, usually at elevated temperature. Deprotection can occur in situ under acidic conditions, if for example P is t-butoxycarbonyl to afford C directly.

Examples of suitable leaving groups L₁ include halogen, OC(═O)alkyl and OC(═O)O-alkyl. The transformation C to D may be carried out in an inert solvent such as dichloromethane, in the presence of a base such as triethylamine. Alternatively this step may be carried out when L₁ represents hydroxy, in which case reaction with C takes place in an inert solvent such as dichloromethane in the presence of a diimide reagent such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and an activator such as 1-hydroxybenzotriazole. Also when L₁ represents hydroxy the reaction can be effected using O-(7-azabenzotrazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU) with a base such as triethylamine or N,N-diisopropylethylamine.

Wherein Het, X and Ar² are as defined for formula I and P is a protecting group. Suitable reducing agents include sodium borohydride which can be used at ambient temperature in methanol.

Wherein Het, X and Ar² are as defined for formula I, P is a protecting group and M is a metal for example lithium.

Within the schemes above there is scope for functional group interconversion; conversion of one compound of formula (I) to another of formula (I) by interconversion of substituents.

The compounds of formula (I) may be prepared singly or as compound libraries comprising at least 2, e.g. 5 to 1000, preferably 10 to 100 compounds of formula (I). Compound libraries may be prepared by a combinatorial ‘split and mix’ approach or by multiple parallel synthesis using either solution phase or solid phase chemistry, by procedures known to those skilled in the art.

Thus according to a further aspect of the invention there is provided a compound library comprising at least 2 compounds of formula (I), or pharmaceutically acceptable derivatives thereof.

Pharmaceutically acceptable salts may be prepared conventionally by reaction with the appropriate acid or acid derivative.

The compounds of formula (I) and their pharmaceutically acceptable derivatives are useful for the treatment of diseases or disorders where an antagonist of a human orexin receptor is required such as obesity and diabetes; prolactinoma; hypoprolactinemia; hypothalamic disorders of growth hormone deficiency; idiopathic growth hormone deficiency; Cushings syndrome/disease; hypothalamic-adrenal dysfunction; dwarfism; sleep disorders; sleep apnea; narcolepsy; insomnia; parasomnia; jet-lag syndrome; sleep disturbances associated with diseases such as neurological disorders, neuropathic pain and restless leg syndrome; heart and lung diseases; depression; anxiety; addictions; obsessive compulsive disorder; affective neurosis/disorder; depressive neurosis/disorder; anxiety neurosis; dysthymic disorder; behaviour disorder; mood disorder; sexual dysfunction; psychosexual dysfunction; sex disorder; sexual disorder; schizophrenia; manic depression; delerium; dementia; bulimia and hypopituitarism. The compounds of formula (I) or pharmaceutically acceptable derivatives thereof are also useful in the treatment of stroke, particular ischaemic or haemorrhagic stroke. Furthermore the compounds of formula (I) or pharmaceutically acceptable derivatives useful in the blocking an emetic response.

The compounds of formula (I) and their pharmaceutically acceptable derivatives are particularly useful for the treatment of obesity, including obesity associated with Type 2 diabetes, and sleep disorders. Additionally the compounds are useful in stroke and/or blocking the emetic response i.e. nausea and vomiting.

A further aspect of the invention is the use of

-   (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(1H-indol-3-ylmethyl)piperazine; -   (2R)-1-(3,5-dichlorobenzoyl)-2-[(1H-indol-3-yl)methyl]piperazine; -   (2R)-2-[1H-indol-3-yl)methyl]-1-[3-methoxy-5-trifluoromethyl)benzoyl]piperazine;     or -   1-benzolyl-2-[1H-indol-3-yl)methyl]piperazine; as an orexin     antagonist.

Other diseases or disorders which may be treated in accordance with the invention include disturbed biological and circadian rhythms; adrenohypophysis disease; hypophysis disease; hypophysis tumor/adenoma; adrenohypophysis hypofunction; functional or psychogenic amenorrhea; adrenohypophysis hyperfunction; migraine; hyperalgesia; pain; enhanced or exaggerated sensitivity to pain such as hyperalgesia, causalgia and allodynia; acute pain; burn pain; atypical facial pain; neuropathic pain; back pain; complex regional pain syndromes I and II; arthritic pain; sports injury pain; pain related to infection e.g. HIV, post-polio syndrome and post-herpetic neuralgia; phantom limb pain; labour pain; cancer pain; post-chemotherapy pain; post-stroke pain; post-operative pain; neuralgia; and tolerance to narcotics or withdrawal from narcotics.

The invention also provides a method of treating or preventing diseases or disorders where an antagonist of a human orexin receptor is required, which comprises administering to a subject in need thereof an effective amount of a compound of formula (I), or a pharmaceutically acceptable derivative thereof.

The invention also provides a compound of formula (I), or a pharmaceutically acceptable derivative thereof, for use in the treatment or prophylaxis of diseases or disorders where an antagonist of a human orexin receptor is required.

The invention also provides the use of a compound of formula (I), or a pharmaceutically acceptable derivative thereof, in the manufacture of a medicament for the treatment or prophylaxis of diseases or disorders where an antagonist of a human orexin receptor is required.

A further aspect of the invention is the use of (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(1H-indol-3-ylmethyl)piperazine in the manufacture of a medicament for the treatment or prophylaxis of diseases or disorders where an antagonist of a human orexin receptor is required.

For use in therapy the compounds of the invention are usually administered as a pharmaceutical composition. The invention also provides a pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically acceptable derivative thereof, and a pharmaceutically acceptable carrier.

The compounds of formula (I) and their pharmaceutically acceptable derivatives may be administered by any convenient method, e.g. by oral, parenteral, buccal, sublingual, nasal, rectal or transdermal administration, and the pharmaceutical compositions adapted accordingly.

The compounds of formula (I) and their pharmaceutically acceptable derivatives which are active when given orally can be formulated as liquids or solids, e.g. as syrups, suspensions, emulsions, tablets, capsules or lozenges.

A liquid formulation will generally consist of a suspension or solution of the active ingredient in a suitable liquid carrier(s) e.g. an aqueous solvent such as water, ethanol or glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring and/or colouring agent.

A composition in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations, such as magnesium stearate, starch, lactose, sucrose and cellulose.

A composition in the form of a capsule can be prepared using routine encapsulation procedures, e.g. pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), e.g. aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule.

Typical parenteral compositions consist of a solution or suspension of the active ingredient in a sterile aqueous carrier or parenterally acceptable oil, e.g. polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration.

Compositions for nasal administration may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations typically comprise a solution or fine suspension of the active ingredient in a pharmaceutically acceptable aqueous or non-aqueous solvent and are usually presented in single or multidose quantities in sterile form in a sealed container which can take the form of a cartridge or refill for use with an atomising device. Alternatively the sealed container may be a disposable dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve. Where the dosage form comprises an aerosol dispenser, it will contain a propellant which can be a compressed gas e.g. air, or an organic propellant such as a fluorochlorohydrocarbon or hydrofluorocarbon. Aerosol dosage forms can also take the form of pump-atomisers.

Compositions suitable for buccal or sublingual administration include tablets, lozenges and pastilles where the active ingredient is formulated with a carrier such as sugar and acacia, tragacanth, or gelatin and glycerin.

Compositions for rectal administration are conveniently in the form of suppositories containing a conventional suppository base such as cocoa butter.

Compositions suitable for transdermal administration include ointments, gels and patches.

Preferably the composition is in unit dose form such as a tablet, capsule or ampoule.

The dose of the compound of formula (I), or a pharmaceutically acceptable derivative thereof, used in the treatment or prophylaxis of the abovementioned disorders or diseases will vary in the usual way with the particular disorder or disease being treated, the weight of the subject and other similar factors. However, as a general rule, suitable unit doses may be 0.05 to 1000 mg, more suitably 0.05 to 500 mg. Unit doses may be administered more than once a day for example two or three times a day, so that the total daily dosage is in the range of about 0.01 to 100 mg/kg; and such therapy may extend for a number of weeks or months. In the case of pharmaceutically acceptable derivatives the above figures are calculated as the parent compound of formula (I).

No toxicological effects are indicated/expected when a compound of formula (I) is administered in the above mentioned dosage range.

Human orexin-A has the amino acid sequence:

(SEQ ID NO:1) pyroGlu Pro Leu Pro Asp Cys Cys Arg Gln Lys Thr  1              5                 10 Cys Ser Cys Arg Leu Tyr Glu Leu Leu His Gly Ala       15                        20 Gly Asn His Ala Ala Gly Ile Leu Thr Leu-NH₂    25                 30

Orexin-A can be employed in screening procedures for compounds which inhibit the ligand's activation of the orexin-1 receptor.

In general, such screening procedures involve providing appropriate cells which express the orexin-1 receptor on their surface. Such cells include cells from mammals, yeast, Drosophila or E. coli. In particular, a polynucleotide encoding the orexin-1 receptor is used to transfect cells to express the receptor. The expressed receptor is then contacted with a test compound and an orexin-1 receptor ligand to observe inhibition of a functional response. One such screening procedure involves the use of melanophores which are transfected to express the orexin-1 receptor, as described in WO 92/01810.

Another screening procedure involves introducing RNA encoding the orexin-1 receptor into Xenopus oocytes to transiently express the receptor. The receptor oocytes are then contacted with a receptor ligand and a test compound, followed by detection of inhibition of a signal in the case of screening for compounds which are thought to inhibit activation of the receptor by the ligand.

Another method involves screening for compounds which inhibit activation of the receptor by determining inhibition of binding of a labelled orexin-1 receptor ligand to cells which have the receptor on their surface. This method involves transfecting a eukaryotic cell with DNA encoding the orexin-1 receptor such that the cell expresses the receptor on its surface and contacting the cell or cell membrane preparation with a compound in the presence of a labelled form of an orexin-1 receptor ligand. The ligand may contain a radioactive label. The amount of labelled ligand bound to the receptors is measured, e.g. by measuring radioactivity.

Yet another screening technique involves the use of FLIPR equipment for high throughput screening of test compounds that inhibit mobilisation of intracellular calcium ions, or other ions, by affecting the interaction of an orexin-1 receptor ligand with the orexin-1 receptor.

All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.

The following Examples illustrate the preparation of pharmacologically active compounds of the invention. The Descriptions D1-D83 illustrate the preparation of intermediates to compounds of the invention.

In the Examples ¹H NMR's were measured at 250 MHz in CDCl₃ unless otherwise stated.

The following abbreviations are used herein; PyBop means benzotriazol-1-yloxytris(pyrrolidino)phosphonium hexafluorophosphate THF means tetrahyrdofuran EDC.HCL means 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride HATU means O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate TFA means trifluoroacetatic acid DMF means N,N-dimethylformamide DME means 1,2-dimethoxyethane

Description 1: (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine

To (RS)-1-(tert-butyloxycarbonyl)-2-piperidine carboxylic acid (2.64 g, 11.5 mmol) in dichloromethane (10 ml) was added sequentially N,O-dimethyl hydroxylamine (1.34 g, 13.7 mmol), triethylamine (6 ml, 43.0 mmol) and Py.Bop (6.60 g, 12.7 mmol). The resultant mixture was stirred at ambient temperature for 6 h, then diluted with dichloromethane (170 ml) and poured into 1M HCl (22 ml). The organic phase was separated and washed with saturated aqueous sodium hydrogen carbonate (3×25 ml) and brine (25 ml) then evaporated in vacuo. The resultant colourless oil was chromatographed on silica gel eluting with 20% ethyl acetate in hexane to give the title compound (2.43 g, 77%) as a colourless oil.

Mass spectrum (API⁺): Found 273 (MH⁺). C₁₃H₂₄N₂O₄ requires 272.

Description 2: (RS)-2-(2-Benzofuranylcarbonyl)-1-(tert-butyloxycarbonyl)piperidine

To a solution of benzofuran (0.37 ml, 3.36 mmol) in THF (40 ml) at −35° C. was added nbutyllithium (1M in THF) (3.34 ml, 3.34 mmol) over 3 min. The resultant mixture was stirred for 10 min. at −35° C. then (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine (1.0 g, 3.68 mmol) in THF (5 ml) was added over 1 min. and the resultant solution stirred for 15 min. at −35° C. The mixture was poured into saturated ammonium chloride (20 ml) and extracted with ethyl acetate (3×20 ml). The combined organics were washed with saturated aqueous sodium hydrogen carbonate (15 ml), then evaporated in vacuo. The resultant residue was chromatographed on silica gel eluting with 10% ethyl acetate in hexane to give the title compound (0.32 g, 26%) as a yellow solid.

Mass spectrum (API⁺): Found 330 (MH⁺) C₁₉H₂₃NO₄ requires 329.

Description 3: (RS)-2-(2-Benzofuranylmethyl)piperidine

To a solution of (RS)-2-(2-benzofuranylcarbonyl)-1-(tert-butyloxycarbonyl)piperidine (0.30 g, 0.91 mmol) in diethylene glycol (20 g), was added hydrazine hydrate (0.16 ml, 2.79 mmol) and the resultant mixture heated at 170° C. for 30 min. then cooled to room temperature. Potassium hydroxide (0.44 g, 7.86 mmol) was added and the mixture heated at 200° C. for 18 h. The resultant was then poured into water (100 ml) and extracted with diethyl ether (3×20 ml). The combined organic extracts were dried (Na₂SO₄) and evaporated in vacuo to give the title compound (10 mg, 36%) as a golden oil.

Mass spectrum (API⁺). Found 216 (MH⁺) C₁₄H₁₇NO requires 215.

Description 4: (RS)-2-[(2-Hydroxy-phenylcarbamoyl)-methyl]-piperidine-1-carboxylic acid tert butyl ester

A mixture of 2-carboxymethyl-piperidine-1-carboxylic acid tert butyl ester (0.97 g), (Peschke, Bernd; Ankersen, Michael; Hansen, Birgit Sehested; Hansen, Thomas Kruse; Johansen, Nils Langeland; Lau, Jesper; Madsen, Kjeld; Petersen, Hans; Thogersen, Henning; Watson, Brett. Eur. J. Med. Chem. (1999), 34(5), 363-380) in dimethylformamide (8.0 ml) was treated sequentially with EDC.HCl (0.76 g), 2-aminophenol (0.43 g) and 1-hydroxybenzotriazole (0.05 g). The mixture was stirred for 2 h, diluted with ethyl acetate and washed with water, dried (MgSO₄) and solvent removed at reduced pressure to give the title compound (1.29 g) as a gum.

Mass Spectrum (API⁺): Found 335 (MH⁺). C₁₈H₂₆N₂O₄ requires 334

Description 5 (RS)-2-Benzooxazol-2-ylmethyl-piperidine-1-carboxylic acid tert butyl ester

(RS)-2-[(2-Hydroxy-phenylcarbamoyl)-methyl]-piperidine-1-carboxylic acid tert butyl ester (1.25 g), 4-toluenesulphonic acid (0.07 g) and 4-N,N-dimethylaminopyridine (0.023 g) were combined in 1,3-dichlorobenzene (30 ml) and the mixture boiled for 48 h. The mixture was diluted with dichloromethane and washed with water. The organic phase was dried (MgSO₄) and solvent removed at reduced pressure. The residue was column chromatographed (silica gel, 0→1% methanol in dichloromethane) to give the title compound (0.50 g)

Mass Spectrum (API⁺): Found 317 (MH⁺). C₁₈H₂₄N₂O₃ requires 316.

Description 6: (RS)-2-Piperidin-2-ylmethyl-benzooxazole

(RS)-2-Benzooxazol-2-ylmethyl-piperidine-1-carboxylic acid tert butyl ester (0.50 g) in dichloromethane (8 ml) was cooled (ice-bath) and trifluoroacetic acid (2 ml) added. The mixture was stirred with ice-cooling for 4 h, poured onto saturated potassium carbonate (20 ml) and extracted with dichloromethane. The combined extracts were dried (MgSO₄) and solvent removed at reduced pressure to give the title compound (0.10 g)

Mass Spectrum (API⁺): Found 217 (MH⁺). C₁₃H₁₆N₂O requires 216.

Description 7: (RS)-2-[1-(5-Fluoro-benzofuran-2-yl)methanoyl)-piperidine-1-carboxylic acid tert-butyl ester

The title compound was prepared using the method of Description 2, from 5-fluorobenzofuran (1.36 g, 10 mmol, for preparation see WO99/51575), as a pale yellow solid (2.81 g, 84%)

¹H NMR δ: 1.20-1.60 (1H, m), 1.60-1.85 (2H, m), 1.90 (1H, broad m), 2.15-2.30 (1H, broad m), 3.20-3.40 (1H, broad m), 3.85-4.05 (1H, broad m), 5.20-5.70 (1H, broad m), 7.10-7.25 (1H, m), 7.25-7.4 (1H, d, J=7.4 Hz), 7.45-7.75 (2H, m).

Description 8: (RS)-2-(5-Fluoro-benzofuran-2-ylmethyl)-piperidine

The title compound was prepared using the method of Description 3, from (RS)-2-[1-(5-Fluoro-benzofuran-2-yl)methanoyl)-piperidine-1-carboxylic acid tert-butyl ester, D7 (1.21 g, 3.49 mmol), as a pale yellow gum (0.72 g, 89%).

Mass spectrum (API⁺): Found 234 (MH⁺) C₁₄H₁₆FNO requires 233.

Description 9: (RS)-1-Benzofuran-2-yl-1-piperidin-2-yl-methanone

A solution of (RS)-2-(2-benzofuranylcarbonyl)-1-(tert-butyloxycarbonyl)piperidine, D2 (0.86 g, 2.61 mmol) in trifluoroacetic acid (5 ml) and dichloromethane (20 ml) was warmed at 35° C. for 0.5 h. The reaction mixture was evaporated in vacuo and the residue partitioned between dichloromethane (30 ml) and 1N sodium hydroxide (30 ml). The aqueous layer was extracted with dichloromethane (30 ml) and the combined organic layers dried (Na₂SO₄) and evaporated in vacuo to afford the title compound as a pale yellow gum (0.59 g, 99%).

Mass spectrum (API⁺): Found 230 (MH⁺). C₁₄H₁₅NO₂ requires 229.

Description 10: (RS)-2-(1-Furo[2,3-b]pyridin-2-yl)methanoyl-piperidine-1-carboxylic acid tert-butyl ester

2.5N n-Butylithium in hexanes (2.3 ml, 5.75 mmol) was added dropwise over 10 min to a stirred solution of furo[2,3-b]pyridine (0.57 g, 4.79 mmol) (H. Sliwa, Bull. Soc. Chim. France, 646, 1970) in anhydrous THF (20 ml) at −75° C. under argon. The resultant mixture was stirred for 5 min at −70° C. then a solution of (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (1.41 g, 5.19 mmol) in anhydrous THF (20 ml) was added over 2 min. and the resultant solution stirred at −70° C. for 15 min. The mixture was poured into saturated ammonium chloride (100 ml) and extracted with ethyl acetate (2×50 ml). The combined organics were dried (Na₂SO₄) and evaporated in vacuo. The residue was chromatographed on silica gel eluting with 0-1% ethyl acetate in dichloromethane to give the title compound as a colourless solid (0.51 g, 32%).

¹H NMR δ: 1.25-1.55 (11H, m), 1.60-1.80 (2H, m), 1.85-2.05 (1H, broad m), 2.15-2.40 (1H, broad m), 3.15-3.40 (1H, broad m), 3.80-4.15 (1H, broad m), 5.35-5.65 (1H, broad m), 7.30 (1H, broad m), 7.56 (1H, broad s), 8.08 (1H, broad m), 8.53 (1H, broad m).

Description 11: (RS)-2-Piperidin-2-ylmethyl-furo[2,3-b]pyridine

The title compound was prepared using the method of Description 3, from (RS)-2-(1-furo[2,3-b]pyridin-2-yl)methanoyl)piperidine-1-carboxylic acid tert-butyl ester, D10 (0.51 g, 1.55 mmol), as a light brown gum (0.26 g, 74%).

Mass spectrum (API⁺): Found 217 (MH⁺) C₁₃H₁₆N₂O requires 216.

Description 12: (RS)-2-(1-Quinolin-2-yl-methanoyl)-piperidine-1-carboxylic acid tert-butyl ester

30% Potassium hydride dispersed in mineral oil (0.8 g, 6 mmol) was added to a stirred solution of 2-bromoquinoline (1.12 g, 5.29 mmol) (O. Sugimoto, Tet. Lett. 4, (1999), 7477-8) in anhydrous THF (20 ml) at −70° C. under argon. To this was added 2N n-butyllithium in hexanes (2.7 ml, 6.75 mmol) dropwise over 5 min. The resultant mixture was stirred for 10 min at −70° C. then a solution of (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (1.57 g, 5.77 mmol) in anhydrous THF (10 ml) was added over 2 min. The cooling bath was removed and the reaction mixture allowed to warm to −20° C. and held at −20° C. for 10 min. The mixture was poured into saturated ammonium chloride (300 ml) and extracted with ethyl actetate (2×100 ml). The combined organics were dried (Na₂SO₄) and evaporated in vacuo. The residue was chromatographed on silica gel eluting with 0-10% ethyl acetate in pentane to yield the title compound as a pale yellow solid (1.2 g, 66%).

¹H NMR δ: 1.2-1.65 (12H, m), 1.65-1.85 (1H, m), 1.90-2.10 (1H, m), 2.20-2.50 (1H, m), 3.30-3.60 (1H, m), 3.85-4.20 (1H, m), 6.20-6.40 (1H, m), 7.50-7.90 (3H, m), 8.07 (1H, d, J=8.4 Hz), 8.18 (1H, d, J=8.8 Hz), 8.20-8.35 (1H, m).

Description 13: (RS)-2-Piperidin-2-ylmethyl-quinoline

The title compound was prepared using the method of Description 3, from (RS)-2-(1-quinolin-2-yl-methanoyl)-piperidine-1-carboxylic acid tert-butyl ester, D12 (1.2 g, 3.66 mmol), as a pale brown gum (0.053 g, 6%)

Mass spectrum (Electrospray LC/MS): Found 227 (MH⁺). C₁₅H₁₈N₂ requires 226.

Description 14: 2-Amino-N,N-dimethyl-3-nitro-benzamide

EDC.HCl (2.47 g, 12.88 mmol) was added to a stirred mixture of 2-amino-3-nitrobenzoic acid (2.18 g, 11.98 mmol) (Mickelson, J. Med. Chem., 39(23) 4662 (1996)), 2M dimethylamine in THF (6.45 ml, 12.9 mmol) and 1-hydroxybenzotriazole (0.1 g, 0.74 mmol) in dichloromethane (100 ml). The reaction mixture was stirred at room temperature for 18 h, washed with saturated aqueous sodium bicarbonate and the organic layer dried (Na₂SO₄) and evaporated in vacuo to afford the title compound as a pale orange gum (2.5 g, 100%).

¹H NMR δ: 3.08 (6H, s), 6.70 (1H, m), 6.85 (2H, broad s), 7.33 (1H, dd, J=2 and 8 Hz), 8.2 (1H, dd, J=2 and 8 Hz).

Description 15: 3-Dimethylaminomethyl-benzene-1,2-diamine

1M Lithium aluminium hydride in THF (18.1 ml, 18.1 mmol) was added dropwise over 5 min. to a stirred, ice cooled solution of 2-Amino-N,N-dimethyl-3-nitro-benzamide, D14 (1.26 g, 6.03 mmol) in anhydrous THF (40 ml) under argon. The reaction mixture was stirred at 0° C. for 0.5 h then at room temperature for a further 2 h before being recooled in ice, as water (3.2 ml), 2N sodium hydroxide (3.6 ml) and water (3.2 ml) were added dropwise sequentially. The mixture was stirred for 10 min, solid Na₂SO₄ added and stirring continued for 10 min. Solids were filtered, washed with ethyl acetate and the combined organics evaporated in vacuo to give the title compound as an orange solid (0.9 g, 91%).

¹H NMR δ: 2.19 (6H, s), 3.29 (2H, broad s), 3.42 (2H, s), 4.50 (2H, broad s), 6.50-6.80 (3H, m).

Description 16: (RS)-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-acetic acid methyl ester

A stirring solution of 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (3.00 g, 12.5 mmol) in DMF (50 ml), under argon was treated sequentially with N,N-diisopropylethylamine (6.8 ml), HATU (4.77 g, 12.5 mmol) then after stirring for 0.25 h, piperidin-2-yl-acetic acid methyl ester (Beckett et al, J. Med. Chem., 563, 1969) (1.83 g, 12.5 mmol) was added. The mixture was stirred for 16 h at room temperature and was then diluted with water. The product was extracted into diethyl ether. The organic phase was washed with water (3×) and brine, was dried (MgSO₄) and the solvent removed in vacuo to afford the title compound as a yellow gum (4.00 g, 85%).

Mass spectrum (API⁺). Found 377 (MH⁺). C₁₉H₂₁FN₂O₃S requires 376.

Description 17: (RS)-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-acetic acid

A stirring solution of (1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-acetic acid methyl ester, D16 (4.00 g, 10.6 mmol) in methanol/water (75 ml/25 ml) was treated with sodium hydroxide (0.85 g, 21.3 mmol). The mixture was stirred for 16 h at room temperature. The methanol was removed in vacuo and the residue was diluted with water and extracted with diethyl ether (2×). The aqueous phase was acidified with 5N HCl and the product was extracted with ethyl acetate. The organic phase was dried (MgSO₄) and the solvent removed in vacuo. The residue was triturated with pentane to afford the title compound as a white solid (3.10 g, 82%).

¹H NMR (D₆-DMSO) δ: 0.98 (0.6H, m), 1.15-1.70 (5.4H, bm), 2.18 (0.4H, dd), 2.38 (0.6H, dd, J=6 and 15 Hz), 2.70 (4.4H, m), 2.93 (0.6H, m), 3.17 (0.6H, d, J=12 Hz), 3.94 (0.4H, m), 4.40 (0.4H, d, J=12 Hz), 5.05 (0.6H, m), 7.27 (2H, m), 7.47 (2H, m), 12.20 (1H, bs).

Description 18: (RS)-5,6-Difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole

A mixture of 2-carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (Beckett et al, J. Med. Chem., 563, 1969) (10.0 g, 41 mmol) and 4,5-difluoro-benzene-1,2-diamine (5.95 g, 41 mmol) in polyphosphoric acid (140 g) was heated at 140° C. for 7 h. The cooled reaction mixture was poured onto excess solid potassium carbonate and crushed ice. The resulting basic, aqueous solution was extracted with ethyl acetate (2×) and the combined organics were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. The residue was triturated with diethyl ether, ethyl acetate and pentane to afford the title compound as a light brown solid (7.14 g, 69%).

¹H NMR (D₆-DMSO) δ: 1.08 (1H, m), 1.27 (2H, m), 1.50 (2H, m), 1.70 (1H, m), 2.48 (1H, m, obscured by DMSO), 2.78 (2H, d, J=7 Hz), 2.88 (2H, m), 7.51 (2H, app.t, J=6 Hz).

Description 19: (RS)-2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester

4,5-Difluoro-benzene-1,2-diamine (1.00 g, 6.9 mmol) and 2-carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (Beckett et al, J. Med. Chem., 563, 1969) (1.69 g, 6.9 mmol) were heated at 120° C. with stirring, under argon for 4 h. A further portion of 2-carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (0.85 g) was added and heating was continued for a further 2 h. The cooled reaction mixture was diluted with ethyl acetate, washed with saturated aqueous sodium bicarbonate (2×) and brine, dried (MgSO₄) and the solvent removed in vacuo. The residue was chromatographed (silica gel, 0-30% ethyl acetate-pentane) to give a yellow solid which was triturated with diethyl ether to afford the title compound as a pale brown solid (0.38 g, 15%).

Mass spectrum (API⁺). Found 352 (MH⁺) C₁₈H₂₃F₂N₃O₂ requires 351.

Description 20: (RS)-5,6-Difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole. 2HCl

A stirring solution of 2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester, D19 (375 mg, 1.1 mmol) in MeOH (20 ml) was treated with 1M HCl in 1,4-dioxane (5 ml). After stirring under argon at room temperature for 5 h the volatiles were removed in vacuo to afford the title compound as a gum (100%). Mass spectrum (API⁺). Found 252 (MH⁺) C₁₃H₁₅F₂N₃ requires 251.

Description 21: (RS)-4,5-Difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole

A mixture of 2-carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (Beckett et al, J. Med. Chem., 563, 1969) (6.72 g, 28 mmol) and 3,4-difluoro-benzene-1,2-diamine (4.00 g, 28 mmol) in polyphosphoric acid (130 g) was heated at 140° C. for 7.5 h. The cooled reaction mixture was poured onto excess solid potassium carbonate and crushed ice. The resulting basic, aqueous solution was extracted with ethyl acetate (2×) and the combined organics were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. The residue was triturated with diethyl ether, ethyl acetate and pentane to afford the title compound as a white solid (4.29 g, 62%).

¹H NMR (D₆-DMSO) δ: 1.08 (1H, m), 1.28 (2H, m), 1.50 (2H, m), 1.72 (1H, m), 2.46 (1H, m, obscured by DMSO), 2.81 (2H, d, J=7 Hz), 2.90 (2H, m), 7.14 (1H, m), 7.24 (1H, m).

Description 22: 1-(2-Dimethylamino-ethyl)-4-(4-fluoro-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester

4-(4-Fluoro-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester (2.4 g, 10 mmol) was added to an ice-cooled slurry of sodium hydride (0.82 g, 60% dispersion in mineral oil, 20 mmol) in DMF (20 ml), under argon. N,N-diisopropylethylamine (1.8 ml, 10 mmol) was added followed by 2-chloro-ethyl dimethylamine.HCl (1.48 g, 10 mmol) and potassium iodide (5 mg). The reaction mixture was stirred at room temperature for 16 h then at 80° C. for 48 h. 2N HCl and water were added and the product extracted with ethyl acetate (3×). The combined organics were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 3-10% methanol-dichloromethane) afforded 2-(2-dimethylamino-ethyl)-4-(4-fluoro-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester (900 mg) and the title compound (630 mg).

¹H NMR δ: 1.31 (3H, t. J=7 Hz), 2.29 (6H, s), 2.80 (2H, t, J=6 Hz), 4.30 (4H, m), 7.05 (2H, m), 7.44 (2H, m), 7.56 (1H, s).

Description 23: 1-(2-Dimethylamino-ethyl)-4-(4-fluoro-phenyl)-1H-pyrazole-3-carboxylic acid

A solution of 1-(2-Dimethylamino-ethyl)-4-(4-fluoro-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester, D22 (610 mg, 2 mmol) in methanol/water (15 ml/10 ml) was treated with 2N sodium hydroxide (4 ml). After stirring at room temperature for 16 h the methanol was removed in vacuo and the residue treated with 2N HCl (4 ml). The water was removed in vacuo. Dichloromethane was added to the residue and the inorganic solid was removed by filtration. Removal of the solvent form the filtrate in vacuo afforded the title compound as a white solid (350 mg, 63%).

Mass spectrum (API⁺). Found 278 (MH⁺) C₁₄H₁₆FN₃O₂ requires 277.

Description 24: 5-(4-Fluoro-phenyl)-2-methyl-2H-[1,2,3]triazole-4-carboxylic acid methyl ester

5-(4-Fluoro-phenyl)-2H-[1,2,3]triazole-4-carboxylic acid methyl ester (2.21 g, 10 mmol) in THF (10 ml) was added drop-wise to an ice-cooled slurry of sodium hydride (0.42 g, 60% dispersion in mineral oil, 10 mmol) in THF (45 ml), under argon. After stirring at room temperature for 1 h, the reaction mixture was heated at 80° C. for 16 h. Water was added to the cooled mixture and the product was extracted with diethyl ether (2×). The combined organics were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 10-50% ethyl acetate-pentane) afforded 5-(4-Fluoro-phenyl)-1-methyl-2H-[1,2,3]triazole-4-carboxylic acid methyl ester (763 mg, 33%) and the title compound (943 mg, 40%).

¹H NMR δ: 3.94 (3H, s), 4.29 (3H, s), 7.13 (2H, m), 7.87 (2H, m).

Description 25: 5-(4-Fluoro-phenyl)-2-methyl-2H-[1,2,3]triazole-4-carboxylic acid

5-(4-Fluoro-phenyl)-2-methyl-2H-[1,2,3]triazole-4-carboxylic acid methyl ester D24 (940 mg, 4 mmol) in water (65 ml) was treated with 2N sodium hydroxide (4 ml) and the mixture was heated at 120° C. for 2 h. The volume of water was reduced to 20 ml in vacuo and the ice-cooled residue was treated with 2N HCl (4 ml). Filtration, washing with water and drying in vacuo afforded the title compound as a white solid (810 mg, 91%).

Mass spectrum (API⁺). Found 222 (MH⁺) C₁₀H₈FN₃O₂ requires 221.

Description 26: (S)-Pyrrolidin-2-ylmethyl-1H-benzoimidazole

A mixture of benzene-1,2-diamine (0.235 g, 2.2 mmol) and (S)-2-carboxymethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (0.500 g, 2.2 mmol) in polyphosphoric acid (10 g) was heated under argon at 140° C. for 4 h then at 160° C. for 20 h. The reaction mixture was cooled and partitioned between aqueous saturated potassium carbonate and dichloromethane. The aqueous phase was extracted with 9-1 dichloromethane-methanol (4×). The combined organics were dried (MgSO₄) and the solvent removed in vacuo to afford the title compound as a pale brown foam (0.328 g) contaminated with ≈9% starting diamine.

¹H NMR δ: 1.30-2.10 (4H, bm), 2.80-3.60 (6H, bm incl.NH), 7.20 (1H, m), 7.55 (1H, m).

Description 27: (S)-5,6-Difluoro-pyrrolidin-2-ylmethyl-1H-benzoimidazole

A mixture of 4,5-difluorobenzene-1,2-diamine (0.360 g, 2.5 mmol) and (S)-2-carboxymethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (0.570 g, 2.5 mmol) in polyphosphoric acid (9.5 g) was heated under argon at 160° C. for 20 h. The reaction mixture was cooled and partitioned between aqueous saturated potassium carbonate and dichloromethane. The aqueous phase was extracted with 9-1 dichloromethane-methanol (4×). The combined organics were dried (MgSO₄) and the solvent removed at reduced pressure to afford the title compound as a pale brown foam (0.394 g).

Mass Spectrum (API⁺): Found 236 (M-H). C₁₂H₁₃F₂N₃ requires 237.

Description 28: (RS)-[1-(2,2,2-Trifluoroethanoyl)-piperidin-2-yl]acetic acid ethyl ester

(RS)-Piperidin-2-yl acetic acid ethyl ester (Rhodes et al, J. Am. Pharm. Assoc., 1956, 45, 746) (6.0 g) was dissolved in dry dichloromethane (60 ml) and cooled to −10° C. under an atmosphere of argon. Triethylamine (5.0 ml), followed by trifluoroacetic anhydride (5.1 ml) was added to the stirred solution and stirring was continued at room temperature for 16 h. The reaction solution was then partitioned between dichloromethane and saturated sodium bicarbonate solution. The organic solution was dried (MgSO₄) and the solvent removed in vacuo to yield the title compound as an oil (4.2 g).

Mass Spectrum (API⁺): Found 268 (MH⁺). C₁₁H₁₆F₃NO₃ requires 267.

Description 29: (R,S)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-2,2,2-trifluoro-ethanone

[1-(2,2,2-Trifluoroethanoyl)piperidin-2-yl]acetic acid ethyl ester, D28 (1.34 g) and 2-aminothiophenol (1.50 g) were suspended in polyphosphoric acid (30 ml) and heated to 90° C. for 2 h with vigorous stirring. After cooling, the reaction mixture was poured into iced water and stirred vigorously for 1 h. The aqueous solution was then extracted several times with ethyl acetate. After drying (MgSO₄), the solvent was removed in vacuo and the residue chromatographed (silica gel) to afford the title compound as an oil (1.2 g).

Mass Spectrum (API⁺): Found 329 (MH⁺). C₁₅H₁₅F₃N₂SO requires 328.

Description 30: (RS)-2-Piperidin-2-ylmethylbenzothiazole

1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-2,2,2-trifluoroethanone, D29 (1.2 g) was dissolved in methanol (40 ml) and 2N sodium hydroxide solution (20 ml) and heated to 50° C. for 0.75 h. After cooling, the reaction solution was partitioned between dichloromethane and water. The organic solution was dried (MgSO₄) and the solvent removed in vacuo. The residue was chromatographed (silica gel, 0-10% [9:1 MeOH/conc. ammonia solution] in dichloromethane) to afford the title compound (0.68 g).

Mass Spectrum (API⁺): Found 233 (MH⁺). C₁₃H₁₆N₂S requires 232.

Description 31: (RS)-1-Benzyl-2-bromomethylpiperidine

(RS)-(1-Benzyl-piperidin-2-yl)-methanol (R. Sreekumar et al, Tetrahedron Lett., 1998, 39 5151) (10.0 g) was converted to the title compound (5.2 g) by treatment with triphenylphosphine (13.0 g) and N-bromosuccinimide (9.4 g) in dichloromethane using literature procedures, (Tetrahedron Lett, 1999, 40, 7477-8).

Mass Spectrum (API⁺): Found 270 (MH⁺). C₁₃H₁₈ ⁸¹BrN requires 269.

Description 32: (RS)-1-Benzyl-2-cyanomethylpiperidine

(RS)-1-Benzyl-2-bromomethylpiperidine, D31 (4.2 g) was dissolved in dry dimethylsulphoxide (15 ml) and treated with sodium cyanide (5.0 g). The solution was then stirred at 85° C. under argon for 18 h. The reaction solution was then poured into water (300 ml) and extracted with dichloromethane (2×200 ml). The organic solution was dried (MgSO₄) and the solvent removed in vacuo. Chromatography (silica gel, diethyl ether/petroleum ether mixtures) afforded the title compound (3.3 g).

Mass Spectrum (API⁺): Found 215 (MH⁺). C₁₄H₁₈N₂ requires 214.

Description 33: (RS)-2-(1-Benzylpiperidin-2-ylmethyl)-[1,2,4]-triazolo[1,5-a]pyridine

(RS)-1-Benzyl-2-cyanomethylpiperidine, D32 (1.0 g) was dissolved in dry tetrahydrofuran (10 ml) containing ethanol (0.28 ml). The reaction solution was then cooled to ice bath temperature and hydrogen chloride gas was bubbled through the solution for 1 h. The solution was then stirred at room temperature for 16 h. The resulting solution was diluted with tetrahydrofuran (30 ml) and dichloromethane (30 ml) and 1-aminopyridinium iodide (1.0 g), followed by excess potassium carbonate and ethanol (30 ml) was added. The reaction mixture was then stirred at room temperature under argon for 24 h. The mixture was then filtered and the solvent removed in vacuo. The residue was chromatographed (silica gel, 80-20 diethyl ether-petroleum ether then 9-1 dichloromethane-methanol) to afford the title compound.

Mass Spectrum (API⁺): Found 307 (MH⁺). C₁₄H₁₈N₂ requires 306.

Description 34: (RS)-2-Piperidin-2-ylmethyl-5,6,7,8-tetrahydro-[1,2,4]-triazolo[1,5-a]pyridine and 2-Piperidin-2-ylmethyl-[1,2,4]-triazolo[1,5-a]pyridine

(RS)-2-(1-Benzylpiperidin-2-ylmethyl)-[1,2,4]-triazolo[1,5-a]pyridine, D33 (0.200 g) was dissolved in ethanol (25 ml). Palladium hydroxide (0.100 g), followed by platinum IV sulphide (0.020 g) were added and the reaction mixture hydrogenated at 50 psi and 50° C. for 16 h. The suspension was evaporated to yield a mixture of the title compounds (0.180 g).

Description 35: (RS)-2-[(Methoxy-methyl-carbamoyl)-methyl]-piperidine-1-carboxylic acid tert-butyl ester

A solution of 2-carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (Beckett et al, J. Med. Chem., 563, 1969) (2.29 g, 10 mmol) in DMF (20 ml) was treated sequentially with N,N-diisopropylethylamine (4.0 ml), HATU (3.8 g, 10 mmol) and O,N-dimethyl-hydroxylamine.HCl (0.98 g, 10 mmol). The reaction mixture was stirred under argon at room temperature for 16 h. The volatiles were removed in vacuo and the residue was chromatographed (silica gel, diethyl ether) to afford the title compound as a white solid (2.60 g, 90%).

Mass Spectrum (API⁺): Found 187 (MH⁺-^(t)BOC). C₁₄H₂₆N₂O₄ requires 286.

Description 36: (RS)-2(2-Benzofuran-2-yl-2-oxo-ethyl)-piperidine-1-carboxylic acid tert-butyl ester

To a solution of benzofuran (0.95 g, 8.0 mmol) in THF (40 ml), under argon at −40° C. was added n-butyllithium (2.5M in hexanes) (4.00 ml, 10.0 mmol) over 5 min. The resultant mixture was stirred for 15 min. at −40° C. then (RS)-2-[(methoxy-methyl-carbamoyl)-methyl]-piperidine-1-carboxylic acid tert-butyl ester, D35 (2.30 g, 8.0 mmol) in THF (10 ml) was added over 1 min. and the resultant solution stirred for 20 min. at −40° C. The mixture was poured into saturated ammonium chloride (20 ml) and extracted with ethyl acetate (3×). The combined organics were dried (MgSO₄) and the solvent removed in vacuo. The resultant residue was chromatographed (silica gel, dichloromethane) to afford the title compound (2.2 g, 84%).

¹H NMR δ: 1.35 (9H, s), 1.44 (1H, m), 1.65 (5H, m), 2.94 (1H, dt, J=3 and 13 Hz), 3.17 (2H, m), 4.05 (1H, broad d), 4.89 (1H, m), 7.31 (1H, t, J=8 Hz), 7.48 (1H, m), 7.57 (2H, m), 7.72 (1H, d, J=8 Hz).

Description 37: (RS)-1-Benzofuran-2-yl-2-piperidin-2-yl-ethanone

A stirring solution of (RS)-2(2-benzofuran-2-yl-2-oxo-ethyl)-piperidine-1-carboxylic acid tert-butyl ester, D36 (1.68 g, 4.9 mmol) in dichloromethane (20 ml) was treated with trifluoroacetic acid (5 ml). The mixture was stirred at 50° C. for 1 h, cooled and the volatiles removed in vacuo.

The residue was dissolved in dichloromethane and washed with saturated sodium bicarbonate, dried (MgSO₄) and the solvent removed in vacuo to afford the title compound (1.20 g, 99%).

Mass Spectrum (API⁺): Found 244 (MH⁺). C₁₅H₁₇NO₂ requires 243.

Description 38: (RS)-1-Benzofuran-2-yl-2-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-ethanone

The title compound was prepared from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid

and (RS)-1-benzofuran-2-yl-2-piperidin-2-yl-ethanone, D37 according to a procedure similar to that for Description 35.

Mass Spectrum (API⁺): Found 463 (MH⁺). C₂₆H₂₃FN₂O₃S requires 462.

Description 39: (RS)-4-Bromo-2-piperidin-2-ylmethyl-1H-benzimidazole

The title compound was prepared using the method of Description 18 from 3-bromobenzene-1,2-diamine (0.50 g, 2.7 mmol) and 2-carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (0.65 g, 2.7 mmol), as a pale brown amorphous solid (0.70 g, 88%)

Mass spectrum (Electrospray LC/MS): Found M-H 292. C₁₃H₁₆ ⁷⁹BrN₃ requires 293.

Description 40: (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-2,2,2-trifluoro-ethanone

To (RS)-2-(2-Benzofuranylmethyl)piperidine, D3 (500 mg, 2.3 mmol) in dichloromethane containing triethylamine (0.35 ml, 2.5 mmol) at 0° C. under argon was added trifluoroacetic anhydride (0.36 ml, 2.5 mmol) in dichloromethane (3 ml) over 5-10 min. The reaction was stirred at room temperature for 64 h, diluted with dichloromethane and washed sequentially with water and saturated sodium hydrogen carbonate, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel) afforded the title compound as a solid (740 mg, 99%).

¹H NMR δ: 1.50-1.90 (6H, m), 2.90-3.20 (2H, m), 3.27-3.35 (1H, m), 3.85-3.89 (0.66H, m), 4.51-4.54 (0.66H, m), 5.09-5-14 (0.66H, m), 6.48 and 6.50 (1H, s), 7.15-7.25 (2H, m), 7.39-7.45 (1H, m), 7.45-7.50 (1H, m).

Description 41: (RS)-1-(2-(3-Bromo-benzofuran-2-ylmethyl-piperidin-1-yl)-2,2,2-trifluoro-ethanone

To a solution of (RS)-1-(2-benzofuran-2-ylmethyl-piperidin-1-yl)-2,2,2-trifluoro-ethanone, D40 (700 mg, 2.2 mmol) in diethyl ether (10 ml) at −12° C. under argon was added a solution of bromine (360 mg, 2.2 mmol) in dichloromethane (4 ml) drop-wise over 0.3 h. The reaction mixture was allowed to reach room temperature and after 1 h the volatiles were removed in vacuo. Re-evaporation from dichloromethane (3×) afforded the title compound as a solid (840 mg, 96%).

Mass spectrum (Electrospray LC/MS): Found 310 (MH⁺-Br). C₁₆H₁₅ ⁷⁹BrF₃NO₂ requires 389.

Description 42: (RS)-2-(1-(2,2,2-Trifluoro-ethanoyl)-piperidin-2-yl-methyl)-benzofuran-3-carbonitrile

To a solution of (RS)-1-(2-(3-bromo-benzofuran-2-ylmethyl-piperidin-1-yl)-2,2,2-trifluoro-ethanone, D41 (840 mg, 2.1 mmol) in N-methylpyrrolidinone (15 ml) was added copper(I)cyanide (387 mg, 4.2 mmol) and the mixture refluxed for 4.5 h. The reaction mixture was cooled and diluted with water (100 ml), 0.880 ammonia (3 ml) and ethyl acetate (3×). The combined extracts were dried (Na₂SO₄) and the solvent removed in vacuo. The residual oil was redissolved in ethyl acetate (75 ml) and washed with water (4×), brine, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel) afforded the title compound as a solid.

Mass spectrum (Electrospray LC/MS): Found 337 (MH⁺). C₁₇H₁₅F₃N₂O₂ requires 336.

Description 43: (RS)-Morpholin-3-yl-acetic acid ethyl ester

N-chloromorpholine (24 g) in diethyl ether (20 ml) was added drop-wise over 2.5 h to a vigorously stirred solution of potassium hydroxide (22.1 g, 0.37 mol) in ethanol (130 ml) at 90° C. Heating was continued at 80° C. for 2 h. After standing at room temperature for 48 h the mixture was filtered to remove the inorganics and the solvent removed from the filtrate in vacuo. The residue was partitioned between diethyl ether and brine, dried (Na₂SO₄) and the solvent removed in vacuo. The resulting brown oil was dissolved in acetonitrile (100 ml). Triethylamine (25 ml) and monoethyl malonate (25 g) were added and the mixture heated at 16° C. for 16 h. The volatiles were removed in vacuo and the residue partitioned between saturated aqueous potassium carbonate and diethyl ether. The organic phase was dried (Na₂SO₄) and the solvent removed in vacuo to afford the title compound as a brown oil (3.5 g).

Mass Spectrum (API⁺): Found 174 (MH⁺). C₈H₁₅NO₃ requires 173.

Description 44: (RS)-(4-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-morpholin-3-yl)-acetic acid ethyl ester

The title compound (1.48 g, 66%) was prepared from (RS)-morpholin-3-yl-acetic acid ethyl ester, D43 (1.37 g, 5.8 mmol) and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (1.00 g, 5.8 mmol) according to a procedure similar to that described for D16.

Mass spectrum (Electrospray LC/MS): Found 393 (MH⁺). C₁₉H₂₁FN₂O₄S requires 392.

Description 45: (RS)-(4-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-morpholin-3-yl)-acetic acid

The title compound (1.33 g, 99%) was prepared from (RS)-(4-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-morpholin-3-yl)-acetic acid ethyl ester, D44 (1.46 g, 3.7 mmol) according to a procedure similar to that described for D17.

Mass Spectrum (API⁺): Found 363 (M-H). C₁₇H₁₇FN₂O₄S requires 364.

Description 46: (RS)-2-(1-Furo[3,2-b]pyridin-2-yl)methanoyl)piperidine-1-carboxylic acid tert-butyl ester

The title compound was prepared using the method of Description 10 from furo[3,2-b]pyridine (1.14 g, 9.6 mmol) (Shiotani and Morita, J. Het. Chem., 23, 665, 1986), as a pale yellow solid (1.97 g, 62%).

Mass Spectrum (API⁺): Found 331 (MH⁺). C₁₈H₂₂N₂O₄ requires 330.

Description 47: (RS)-2-Piperidin-2-ylmethyl-furo[3,2-b]pyridine

The title compound was prepared using the method of Description 3 from (RS)-2-(1-furo[3,2-b]pyridin-2-yl)methanoyl)piperidine-1-carboxylic acid tert-butyl ester, D46 (1.95 g, 5.9 mmol), as a pale green gum (0.75 g, 59%).

Mass Spectrum (API⁺): Found 217 (MH⁺). C₁₃H₁₆N₂O requires 216.

Description 48: (RS)-2-[1-(5-Fluorobenzofuran-2-yl)-methanoyl]-piperazine-1,4-dicarboxylic acid 1-benzyl ester 4-tert-butyl ester

The title compound was prepared from (RS)-2-(methoxymethylcarbamoyl)piperazine-1,4-dicarboxylic acid 1-benzyl ester 4-tert-butyl ester (1.25 g, 3.07 mmol) (WO01/00214) and 5-fluorobenzofuran (0.42 g, 3.09 mmol) (WO99/51575) by the method of Description 2 as a pale green gum (0.81 g, 55%).

Mass spectrum (API⁺): Found 505 (MNa⁺). C₂₆H₂₇FN₂O₆ requires 482.

Description 49: (RS)-2-[1-(5-Fluoro-benzofuran-2-yl)methanoyl]-piperazine-1-carboxylic acid benzyl ester

The title compound was prepared from (RS)-2-[1-(5-fluorobenzofuran-2-yl)-methanoyl]-piperazine-1,4-dicarboxylic acid 1-benzyl ester 4-tert-butyl ester, D48 (0.81 g, 1.68 mmol) by the method of Description 52 as a pale yellow amorphous solid (0.57 g, 90%).

Mass spectrum (API⁺): Found 383 (MH⁺). C₂₁H₁₉FN₂O₄ requires 382.

Description 50: (RS)-2-[1-(5-Fluoro-benzofuran-2-yl)methanoyl]-4-methyl-piperazine-1-carboxylic acid benzyl ester

97% Formic acid (0.19 g, 4 mmol) was added to a stirred mixture of (RS)-2-[1-(5-fluoro-benzofuran-2-yl)methanoyl]-piperazine-1-carboxylic acid benzyl ester, D49 (0.57 g, 1.5 mmol) in water (5 ml). Stirring was continued as a 37% formaldehyde solution in water (0.155 g) was added. The resultant mixture was heated at 100° C. for 3.5 h, cooled, diluted with water (30 ml) and basified with 2N sodium hydroxide. The mixture was extracted with ethyl acetate (2×) and the combined extracts dried (Na₂SO₄) and the solvent removed in vacuo to afford the title compound (0.57 g, 96%).

Mass spectrum (API⁺): Found 397 (MH⁺). C₂₂H₂₁FN₂O₄ requires 396.

Description 51: (RS)-3-(5-Fluorobenzofuran-2-ylmethyl)-1-methylpiperazine

The title compound was prepared from (RS)-2-[1-(5-fluoro-benzofuran-2-yl)methanoyl]-4-methyl-piperazine-1-carboxylic acid benzyl ester, D50 using the method of Description 3 as a yellow gum (0.43 g).

Mass spectrum (API⁺): Found 249 (MH⁺). C₁₄H₁₇FN₂O require 248.

Description 52: (RS)-2-(Methoxy-methyl-carbamoyl)-piperazine-1-carboxylic acid benzyl ester

A mixture of (RS)-2-(methoxy-methyl-carbamoyl)-piperazine-1,4-dicarboxylic acid 1-benzyl ester 4-tert-butyl ester (WO 01/00214) (5 g, 0.012 mol) in dichloromethane (100 ml) and trifluoroacetic acid (20 ml) was heated at 40° C. for 0.5 h, cooled and evaporated. The residual oil was dissolved in dichloromethane (150 ml) and washed with 1M sodium hydroxide (80 ml). The aqueous phase was re-extracted with dichloromethane (2×) and the combined extracts dried (Na₂SO₄) and the solvent removed in vacuo to give the title compound as an oil (3.6 g, 100%).

Mass spectrum (API⁺): Found 308 (MH⁺). C₁₅H₂₁N₃O₄ requires 307.

Description 53: (RS)-2-(Methoxy-methyl-carbamoyl)-4-methyl-piperazine-1-carboxylic acid benzyl ester

To (RS)-2-(methoxy-methyl-carbamoyl)-piperazine-1-carboxylic acid benzyl ester, D52 (3 g, 10 mmol) in 1,2-dichloroethane (50 ml) was added formaldehyde (0.85 ml of 37% w/w solution in water, 11 mmol) and the mixture stirred at ambient temperature for 0.75 h. Sodium triacetoxyborohydride (2.55 g, 12 mmol) was added portionwise over 0.25 h, and the resulting mixture stirred at ambient temperature for 18 h. The reaction was partitioned between dichloromethane (300 ml) and 1M sodium hydroxide (100 ml). The aqueous was re-extracted with dichloromethane (250 ml) and the combined extracts dried (Na₂SO₄) and the solvent removed in vacuo. The residue was chromatographed on silica gel eluting with ethyl acetate-hexane mixtures to afford the title product (3 g, 96%) as a gum.

Mass spectrum (API⁺): Found 322. C₁₆H₂₃N₃O₄ requires 321.

Description 54: (RS)-2-(Methoxy-methyl-carbamoyl)-4-methyl-piperazine-1-carboxylic acid dimethyl-ethyl ester

A mixture of (RS)-2-(Methoxy-methyl-carbamoyl)-4-methyl-piperazine-1-carboxylic acid benzyl ester, D53 (2.9 g, 9 mmol) and di-tert-butyl dicarbonate (2.4 g, 11 mmol) in ethyl acetate (180 ml) was hydrogenated at NTP over 10% Pd—C (1.45 g, 50% aqueous paste) for 64 h. The mixture was filtered through kieselguhr, washed with ethyl acetate and the filtrate evaporated. The residue was chromatographed on silica gel eluting with ethyl acetate-methanol mixtures to afford the title product as a white solid (2.9 g, 92%).

Mass spectrum (API⁺): Found 288 (MH⁺). C₁₃H₂₅N₃O₄ requires 287.

Description 55: (RS)-2-(1-Benzofuran-2-yl-methanoyl)-4-methyl-piperazine-1-carboxylic acid tert-butyl ester

The title compound (1.81 g, 52%) was prepared from (RS)-2-(methoxy-methyl-carbamoyl)-4-methyl-piperazine-1-carboxylic acid dimethyl-ethyl ester, D54 (2.9 g, 10.1 mmol) and benzofuran (0.74 g, 10.1 mol) using the method of Description 2.

Mass spectrum (API⁺): Found 345 (MH⁺). C₁₉H₂₄N₂O₄ requires 344.

Description 56: (RS)-3-Benzofuran-2-ylmethyl-1-methyl-piperazine

The title compound was obtained from (RS)-2-(1-benzofuran-2-yl-methanoyl)-4-methyl-piperazine-1-carboxylic acid tert-butyl ester, D55 (1.28 g, 3.7 mmol) using the method of Description 3 and was used without purification.

Mass spectrum (API⁺): Found 231 (MH⁺). C₁₄H₁₈N₂O require 230.

Description 57: (RS)-1-(5-Fluoro-benzofuran-2-yl)-1-((RS)-4-methyl-piperazin-2-yl)-methanol

(RS)-2-[1-(5-Fluoro-benzofuran-2-yl)methanoyl]-4-methyl-piperazine-1-carboxylic acid benzyl ester, D50 (0.65 g, 1.6 mmol) in ethyl acetate (20 ml) and methanol (20 ml) was hydrogenated at NTP over 10% Pd—C (0.47 g, 50% w/w paste in water) for 3.5 h. The reaction mixture was filtered through Kieselguhr, washing well with methanol and the filtrate evaporated to afford the title product (0.41 g, 90%).

¹H NMR δ: 2.05 and 2.70 (together 2H, m), 2.12 and 2.62 (together 2H, m), 2.24 (3H, s), 2.94 and 3.12 (2H, m), 3.28 (1H, m), 4.84 (1H, d, J=6 Hz), 6.69 (1H, s), 6.97 (1H, m), 7.19 (1H, dd, J=8 and 2 Hz), 7.36 (1H, dd, J=8 and 4 Hz).

Mass spectrum (API⁺): Found 265 (MH⁺). C₁₄H₁₇N₂O₂ require 264.

Description 58: (RS)-4-Fluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole

(RS)-2-Carboxymethyl-piperidine-1-carboxylic acid tert-butyl ester (1.93 g) was heated with 1,2-diamino-3-fluorobenzene (1.00 g) (Kirk, K. L, J. Org. Chem., 1969, 34, 384) as described in Description 18 to afford the title compound (1.14 g).

Mass Spectrum (API⁺): Found 234 (MH⁺). C₁₃H₁₆FN₃ requires 333.

Description 59: (RS)-2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester

A solution of (RS)-5,6-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D18 (1.5 g) in dichloromethane was treated with triethylamine (0.98 ml), then di-tert-butyl dicarbonate (1.3 g). After stirring for 18 h at room temperature under argon the mixture was diluted with dichloromethane then washed with HCl (2M). The aqueous phase was basified with solid K₂CO₃ and extracted with dichloromethane. The organic phase was washed with aqueous NaHCO₃, brine and dried (MgSO₄). The solvent was removed in vacuo to afford the title compound (2 g).

Mass Spectrum (API⁺): Found 352 (MH⁺). C₁₈H₂₃F₂N₃O₂ requires 351.

Description 60: (RS)-2-(5,6-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester

To a stirred suspension of sodium hydride (0.46 g, 60% dispersion in mineral oil) in dimethylformamide (30 ml) at 0° C., under argon, was added (RS)-2-(5,6-difluoro-1H-benzoimidazol-2-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester, D59 (2 g) and the reaction mixture stirred for a further 30 min. before the addition of iodomethane (0.78 ml). The reaction mixture was then stirred at room temperature for 18 h, a further equivalent of iodomethane (0.35 ml) was added and stirring continued for 24 h. Further portions of sodium hydride (0.23 g, 60% dispersion in mineral oil) and iodomethane (0.35 ml) were added and the reaction stirred for an additional 24 h. After diluting with water, the aqueous layer was extracted with diethyl ether (3×). The combined organics were dried (MgSO₄) and solvent removed in vacuo to afford the title compound (0.5 g).

Mass Spectrum (Electrospray LC/MS): Found 266 (MH⁺-^(t)BOC). C₁₉H₂₅F₂N₃O₂ requires 365.

Description 61: (RS)-5,6-Difluoro-1-methyl-2-piperidin-2-ylmethyl-1H-benzoimidazole

(RS)-2-(5,6-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester, D60 (0.5 g) was treated with trifluoroacetic acid (5 ml) as described for Description 6 to afford the title compound (0.363 g)

Mass spectrum (Electrospray): Found 266 (MH⁺). C₁₄H₁₇F₂N₃ requires 265.

Description 62: (RS)-2-[1-(5-Chloro-benzofuran-2-yl)-methanoyl]-4-methyl-piperazine-1-carboxylic acid tert-butyl ester

The title compound (0.98 g) was prepared from (RS)-2-(methoxy-methyl-carbamoyl)-4-methyl-piperazine-1-carboxylic acid dimethyl-ethyl ester, D54 (1.60 g) and 5-chloro-benzofuran (0.86 g, FP1.537.206) using the method of Description 2.

Mass Spectrum (Electrospray LC/MS): Found 279 (MH⁺-^(t)BOC). C₁₉H₂₃ ³⁵ClN₂O₄ requires 378.

Description 63: 3-(5-Chloro-benzofuran-2-ylmethyl)-1-methyl-piperazine

The title compound (0.61 g) was prepared from (RS)-2-[1-(5-chloro-benzofuran-2-yl)-methanoyl]-4-methyl-piperazine-1-carboxylic acid tert-butyl ester, D62 (0.98 g) using the method of Description 3 and used without purification.

Mass Spectrum (Electrospray LC/MS): Found 265 (MH⁺). C₁₄H₁₇ ³⁵ClN₂O requires 264.

Description 64: (RS)-2-[1-(5,7-Dichloro-benzofuran-2-yl)-methanoyl]-4-methyl-piperazine-1-carboxylic acid tert-butyl ester

The title compound (0.94 g) was prepared from (RS)-2-(methoxy-methyl-carbamoyl)-4-methyl-piperazine-1-carboxylic acid dimethyl-ethyl ester, D54 (1.00 g) and 5,7-dichloro-benzofuran (0.65 g, FP1.537.206) using the method of Description 2.

Mass Spectrum (Electrospray LC/MS): Found 413 (MH⁺). C₁₉H₂₂ ³⁵Cl₂N₂O₄ requires 412.

Description 65: (RS)-3-(5,7-Dichloro-benzofuran-2-ylmethyl)-1-methyl-piperazine

The title compound (0.53 g) was prepared from (RS)-2-[1-(5,7-dichloro-benzofuran-2-yl)-methanoyl]-4-methyl-piperazine-1-carboxylic acid tert-butyl ester, D64 (0.94 g) using the method of Description 3 and used without purification.

Mass Spectrum (API⁺LC/MS): Found 299 (MH⁺). C₁₄H₁₆ ³⁵Cl₂N₂O requires 298.

Description 66: 1-(2-Trimethylsilanyl-ethoxymethyl)-1H-indole

A stirring, ice-cooled solution of indole (5.86 g, 50 mmol) in DMF (130 ml) under argon was treated with sodium hydride (3.3 g, 60% dispersion on mineral oil, 80 mmol) and the reaction mixture then stirred at room temperature for 45 min. After cooling to 0° C. 2,2-(trimethylsilyl)ethoxymethyl chloride (12.5 g, 75 mmol) was added dropwise. The reaction mixture was then stirred at room temperature for 4 h. The DMF was removed in vacuo, the residue was poured into water and the product was extracted with diethyl ether. The combined organics were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 0-20% diethyl ether-40-60 pet.ether) afforded the title compound (12.2 g, 100%).

¹H NMR δ: 0.00 (9H, s), 0.96 (2H, t, J=8 Hz), 3.53 (2H, t, J=8 Hz), 5.55 (2H, s), 6.59 (1H, m), 7.20 (2H, m), 7.30 (1H, m with CHCl₃), 7.55 (1H, dd, J=1 and 8 Hz), 7.70 (1H, dd, J=1 and 8 Hz).

Description 67: (RS)-2-{1-[1-(2-Trimethylsilanyl-ethoxymethyl)-1H-indol-2-yl]-methanoyl}-piperidine-1-carboxylic acid tert-butyl ester

A stirring, ice-cooled solution of 1-(2-trimethylsilanyl-ethoxymethyl)-1H-indole, D66 (742 mg, 3 mmol) in DME (5 ml) was treated drop-wise with n-butyl lithium (2.2 ml, 1.6M in hexanes, 3.5 mmol). The resulting green solution was stirred at 0-5° C. for 15 min. then was treated with (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (952 mg, 3.5 mmol) in DME (2.5 ml). After stirring at this temperature for a further 45 min. saturated aqueous NH₄Cl was added (10 ml) and the product was extracted with diethyl ether. The organics were combined, the solvent removed in vacuo and the residue chromatographed (silica gel, 10% diethyl ether-pentane) to afford the title compound as a colourless oil (510 mg, 37%).

Mass Spectrum (API⁺): Found 359 (MH⁺-^(t)BOC). C₂₅H₃₈N₂O₄Si requires 458.

Description 68: (RS)-2-Piperidin-2-ylmethyl-1-(2-trimethylsilanyl-ethoxymethyl)-1H-indole

The title compound (1.1 g) was prepared from (RS)-2-{1-[1-(2-trimethylsilanyl-ethoxymethyl)-1H-indol-2-yl]-methanoyl}-piperidine-1-carboxylic acid tert-butyl ester, D67 (1.9 g) according to a procedure similar to that for Description 3 and used without purification.

Description 69: (RS)-2-[1-(5-Bromo-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester

The title compound (0.96 g) was prepared from 5-bromo-benzofuran (3.6 g, prepared according to procedures similar to those described in Synth. Commun., 257, (1989)) and (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (4.9 g) according to a procedure similar to that for Description 2.

Mass Spectrum (API⁺): Found 308 (MH⁺-^(t)BOC). C₁₉H₂₂ ⁷⁹BrNO₄ requires 407.

Description 70: (RS)-2-(5-Bromo-benzofuran-2-ylmethyl)-piperidine

The title compound (0.53 g) was prepared from (RS)-2-[1-(5-bromo-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester, D69 (1.00 g) according to a procedure similar to that for Description 3 and used without purification.

Mass Spectrum (API⁺): Found 294 (MH⁺). C₁₄H₁₆ ⁷⁹BrNO requires 293.

Description 71: (RS)-2-[1-(4-Bromo-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester

The title compound (1.45 g) was prepared from 4-bromo-benzofuran (3.65 g, WO0109111) and (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (5.17 g) according to a procedure similar to that for Description 2.

Mass Spectrum (API⁺): Found 308 (MH⁺-^(t)BOC). C₁₉H₂₂ ⁷⁹BrNO₄ requires 407.

Description 72: (RS)-2-(4-Bromo-benzofuran-2-ylmethyl)-piperidine

The title compound (0.90 g) was prepared from (RS)-2-[1-(4-bromo-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester, D71 (1.40 g) according to a procedure similar to that for Description 3 and used without purification.

Description 73: (RS)-2-[1-(3-Methyl-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester

The title compound (300 mg) was prepared from 3-methyl-benzofuran (390 mg) and (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (820 mg) according to a procedure similar to that for Description 2.

Mass Spectrum (API⁺): Found 244 (MH⁺-^(t)BOC). C₂₀H₂₅NO₄ requires 343.

Description 74: (RS)-2-(3-Methyl-benzofuran-2-ylmethyl)-piperidine

The title compound (184 mg) was prepared from (RS)-2-[1-(3-methyl-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester, D73 (300 mg) according to a procedure similar to that for Description 3 and used without purification.

Description 75: 2-[1-(4-Fluoro-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid-tert-butyl ester

The title compound (500 mg) was prepared from 4-fluoro-benzofuran (450 mg) and (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (900 mg) according to a procedure similar to that for Description 2.

Mass Spectrum (API⁺): Found 248 (MH⁺-^(t)BOC). C₁₉H₂₂FNO₄ requires 347.

Description 76: (RS)-2-(4-Fluoro-benzofuran-2-ylmethyl)-piperidine

The title compound (310 mg) was prepared from (RS)-2-[1-(4-fluoro-benzofuran-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester, D75 (500 mg) according to a procedure similar to that for Description 3 and used without purification.

Description 77: (RS)-2-[1-(4,6-Dichloro-benzofuran-2-yl)-methanoyl]-4-methyl-piperazine-1-carboxylic acid tert-butyl ester

The title compound (566 mg) was prepared from 4,6-dichloro-benzofuran (390 mg) and (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (600 mg) according to a procedure similar to that for Description 2.

Description 78: (RS)-3-(4,6-Dichloro-benzofuran-2-ylmethyl)-1-methyl-piperazine

The title compound (527 mg) was prepared from (RS)-2-[1-(4,6-dichloro-benzofuran-2-yl)-methanoyl]-4-methyl-piperazine-1-carboxylic acid tert-butyl ester, D77 (900 mg) according to a procedure similar to that for Description 3 and used without purification.

Mass Spectrum (API⁺): Found 299 (MH⁺). C₁₄H₁₆ ³⁵Cl₂N₂O requires 298.

Description 79: (RS)-2-(Methoxy-methyl-carbamoyl)-pyrrolidine-1-carboxylic acid tert-butyl ester

The title compound was prepared from (RS)-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester (14.8 g) and N,O-dimethylhydroxylamine.HCl (7.37 g) according to a procedure similar to that for Example 4.

Mass Spectrum (Electrospray LC/MS): Found 159 (MH⁺-^(t)BOC). C₁₂H₂₂N₂O₄ requires 258.

Description 80: (RS)-2-(1-Benzofuran-2-yl-methanoyl)-pyrrolidine-1-carboxylic acid tert-butyl ester

The title compound (2.7 g) was prepared from benzofuran (2.29 g) and (RS)-2-(methoxy-methyl-carbamoyl)-pyrrolidine-1-carboxylic acid tert-butyl ester, D79 (5.00 g) according to a procedure similar to that for Description 2.

Mass Spectrum (API⁺): Found 216 (MH⁺-^(t)BOC). C₁₈H₂₂₁NO₄ requires 315.

Description 81: (RS)-2-Benzofuran-2-ylmethyl-pyrrolidine

The title compound (0.57 g) was prepared from (RS)-2-(1-benzofuran-2-yl-methanoyl)-pyrrolidine-1-carboxylic acid tert-butyl ester, D80 (1.00 g) according to a procedure similar to that for Description 3 and used without purification.

Description 82: (RS)-2-(1-Benzo[b]thiophen-2-yl-methanoyl)-piperidine-1-carboxylic acid tert-butyl ester

The title compound (1.60 g) was prepared from benzo[b]thiophene (0.80 g) and (RS)-1-(tert-butyloxycarbonyl)-2-(N-methoxy-N-methylcarbamoyl)-piperidine, D1 (1.62 g) according to a procedure similar to that for Description 2.

Description 83: (RS)-2-Benzo[b]thiophen-2-ylmethyl-piperidine

The title compound (410 mg) was prepared from (RS)-2-(1-benzo[b]thiophen-2-yl-methanoyl)-piperidine-1-carboxylic acid tert-butyl ester, D82 (666 mg) according to a procedure similar to that for Description 3 and used without purification.

EXAMPLE 1 (RS)-2-(2-Benzofuranylmethyl)-1-((5-(4-fluorophenyl)-2-methyl-thiazol-4-yl)-carbonyl)-piperidine

5-(4-(Fluorophenyl)-2-methyl-thiazole-4-carbonyl chloride (136 mg, 0.53 mmol) in dichloromethane (1 ml) was added to a solution of (RS)-2-(2-benzofuranylmethyl)piperidine (104 mg, 0.48 mmol) and triethylamine (0.20 ml, 1.45 mmol) in dichloromethane (4 ml) and the mixture shaken at ambient temperature for 30 min. The resultant was washed with saturated aqueous sodium hydrogen carbonate (8 ml). The organic layer was applied directly onto a pre-packed silica gel column and chromatographed eluting with ethyl acetate hexane mixtures to give the title compound (50 mg, 24%) as an off-white solid.

Mass spectrum (API⁺): found 435 (MH⁺): C₂₅H₂₃FN₂O₂S requires 434.

EXAMPLE 2 (RS)-1-(2-Benzooxazol-2-ylmethyl-piperidin-1-yl)-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

5-(4-Fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (0.05 g) in dimethylformamide (2.5 ml) was treated sequentially with diisopropylethylamine (0.12 ml), [O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate] (0.08 g) and the amine of Description 6 (0.047 g) in dimethylformaide (2.5 ml). The mixture was stirred for 16 h, diluted with ethyl acetate and the organic phase washed with water, dried (MgSO₄) and solvent removed at reduced pressure. The residue was chromatographed (silica gel, 0→30% ethyl acetate:pentane) to give the title compound (0.06 g)

Mass spectrum (API⁺): found 436 (MH⁺): C₂₄H₂₂FN₃O₂S requires 435.

EXAMPLE 3 (RS)-1-(2-Benzooxazol-2-ylmethyl-piperidin-1-yl)-1-[2-(3-methyl-[1,2,4]oxadiazol-5-yl)-phenyl]-methanone

The title compound (0.02 g) was prepared from the amine of Description 6 (0.047 g) and 2-(3-methyl-[1,2,4]oxadiazol-5-yl)-benzoic acid (0.045 g) according to the method of Example 2.

Mass spectrum (API⁺): found 403 (MH⁺): C₂₃H₂₂N₄O₃ requires 402.

EXAMPLE 4 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[4-(4-fluoro-phenyl)-1-methyl-1-H-pyrazol-3-yl]-methane

A mixture of (RS)-2-(2-benzofuranylmethyl)piperidine, D3 (0.108 g, 0.5 mmol), 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (0.11 g, 0.5 mmol), EDC.HCl(0.106 g, 0.55 mmol) and 1-hydroxybenzotriazole (0.01 g, 0.07 mmol) in dichloromethane (4 ml) was shaken for 20 h. The resultant was washed with saturated aqueous sodium bicarbonate (8 ml) and the organic layer was added directly onto a dry 10 g prepacked silica gel cartridge. Elution with 10-100% ethyl acetate in hexane gradient then 1-20% methanol in ethyl acetate gradient afforded the title compound as a colourless amorphous solid (0.059 g, 28%).

¹H NMR (CDCl₃) δ: 1.05-1.30 (1H, m), 1.35-1.80 (5H, m), 2.80-3.20 (3H, m), 3.53 (0.55H, broad m), 3.81 and 3.93 (3H, 2 xs), 4.13 (0.45H, broad m), 4.74 (0.45H, broad m), 5.41 (0.55H, broad m), 6.26 and 6.60 (1H, 2 xs), 6.85 and 6.95 (2H, 2×t, J=8.6 Hz), 7.10-7.55 (7H, m).

Mass spectrum (Electrospray LC/MS): Found 418 (MH⁺). C₂₅H₂₄FN₃O₂ requires 417.

The compounds of Examples 5-22 and 90-91 in Table 1 were prepared from the appropriate amine and acid using similar procedures to that described in Example 4. The compound of Example 13 was prepared as the hydrochloride salts.

TABLE 1

Mass Spectrum (Electrospray Example Ar² R LC/MS) 5

F Found MH⁺ 453. C₂₅H₂₂F₂N₂O₂Srequires 452 6

F Found MH⁺ 422. C₂₃H₂₀FN₃O₂Srequires 421 7

F Found MH⁺ 389. C₂₄H₂₁FN₂O₂requires 388 8

F Found MH⁺ 389. C₂₄H₂₁FN₂O₂requires 388 9

F Found MH⁺ 369. C₂₁H₂₁FN₂O₃requires 368. 10

F Found MH⁺ 482. C₂₆H₂₅F₂N₃O₂Srequires 481. 11

F Found MH⁺ 423. C₂₅H₂₇FN₂O₃requires 422. 12

F Found MH⁺ 422. C₂₂H₁₉F₄NO₃requires 421. 13

H Found MH⁺ 407. C₂₅H₃₀N₂O₃requires 406. 14

H Found MH⁺ 371. C₂₄H₂₂N₂O₂requires 370. 15

H Found MH⁺ 398. C₂₅H₂₃N₃O₂requires 397. 16

H Found MH⁺ 405. C₂₃H₂₁FN₄O₂requires 404. 17

H Found MH⁺ 404. C₂₄H₂₂FN₃O₂requires 403. 18

H Found MH⁺ 451. C₂₅H₂₃FN₂O₃Srequires 450. 19

H Found MH⁺ 371. C₂₄H₂₂N₂O₃requires 370 20

H Found MH⁺ 371. C₂₄H₂₂N₂O₂requires 370. 21

H Found MH⁺ 518. C₃₀H₃₅N₃O₃Srequires 517. 22

H Found MH⁺ 532. C₃₁H₃₇N₃O₃Srequires 531. 90

H Found MH⁺ 447. C₂₆H₂₆N₂O₃Srequires 446.(API LC/MS) 91

H Found MW⁺504. C₂₉H₃₃N₃O₃Srequires 436.

EXAMPLE 23 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-furo[2,3-b]pyridin-2-ylmethyl-piperidin-1-yl)-methanone

The title compound was prepared, using the method of Example 4, from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (0.171 g, 0.72 mmol) and (RS)-2-piperidin-2-ylmethyl-furo[2,3-b]pyridine, D11 (0.13 g, 0.60 mmol) as a colourless solid (0.129 g, 49%).

¹H NMR δ: 0.90-1.20 (1H, m), 1.30-1.85 (5H, m), 2.49 and 2.70 (3H, 2 xs), 2.80-3.20 (3H, m), 3.40 (0.45H, m), 4.10 (0.55H, m), 4.70 (0.55, m), 5.35 (0.45H, m), 6.34 and 6.65 (1H, 2 xs), 6.92 and 7.00 (2H, 2×t, J=8.6 Hz), 7.15 (1H, m), 7.35-7.50 (2H, m), 7.80 (1H, m), 8.23 (1H, m).

Mass spectrum (Electrospray LC/MS): Found 436 (MH⁺). C₂₄H₂₂FN₃O₂S requires 435.

EXAMPLE 24 (RS)-1-[4-(4-Fluoro-phenyl)-1-methyl-1H-pyrazole-3-yl]-(2-furo[2,3-b]pyridin-2-ylmethyl-piperidin-1-yl)methanone

The title compound was prepared using the method of Example 4, from 4-(4-(fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (0.159 g, 0.72 mmol) and (RS)-2-piperidin-2-ylmethyl-furo[2,3-b]pyridine, D11 (0.13 g, 0.60 mmol) as a colourless solid (0.12 g, 48%).

Mass Spectrum (Electrospray LC/MS): Found 419 (MH⁺). C₂₄H₂₃FN₄O₂ requires 418.

EXAMPLE 25 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-quinolin-2-ylmethyl-piperidin-1-yl)-methanone

The title compound was prepared, using the method of Example 1, from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (0.09 g, 0.35 mmol) and 2-piperidin-2-ylmethyl-quinoline, D13 (0.053 g, 0.23 mmol) as a colourless solid (0.038 g, 37%).

¹H NMR (DMSO-d₆) δ: 1.00-1.90 (6H, m), 2.37 and 2.66 (3H, 2 xs), 2.90-3.30 (3.5H, m), 4.15 (0.5H, m), 4.45 (0.5H, m), 5.25 (0.5H, m), 7.05 (2H, m), 7.10-7.85 (6H, m), 7.90 (1H, m), 8.05-8.30 (1H, 2 xd, J=8.4 Hz).

Mass spectrum (Electrospray LC/MS): Found 446 (MH⁺). C₂₆H₂₄FN₃OS requires 445.

EXAMPLE 26 (RS)-1-Benzofuran-2-yl-1-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-methanone

The title compound was prepared, using the method of Example 1, from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (0.1 g, 0.39 mmol) and (RS)-1-benzofuran-2-yl-1-piperidin-2-yl-methanone, D9 (0.1 g, 0.43 mmol) as a colourless solid (0.074 g, 43%)

Mass spectrum (Electrospray LC/MS): Found 449 (MH⁺). C₂₅H₂₁FN₂O₃S requires 448.

EXAMPLE 27 (RS)-1-[2-(1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-acetic acid, D17 (110 mg, 0.3 mmol) and benzene-1,2-diamine (33 mg, 0.3 mmol) in PPA (2 g) were heated at 140° C. for 3.5 h. The cooled reaction mixture was poured onto a mixture of crushed ice and K₂CO₃. The basic aqueous solution was extracted with ethyl acetate (3×). The combined organics were washed with brine, dried (MgSO₄) and the solvent removed in vacuo. Chromatography (silica gel, ethyl acetate) afforded the title compound as a dark yellow gum (72 mg, 52%).

Mass Spectrum (Electrospray LC/MS): Found 435 (MH⁺). C₂₄H₂₃FN₄OS requires 434.

The compounds of the Examples 28-34 in Table 2 below were prepared from the appropriate benzene-1,2-diamine and (RS)-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-acetic acid, D17 using similar procedures to that described in Example 27.

TABLE 2

Mass Spectrum Example X (Electrospray LC/MS) 28 5-Cl Found MH⁺ 469. C₂₄H₂₂ ³⁵ ClFN₄OS requires 468. 29 5-F Found MH⁺ 453. C₂₄H₂₂F₂N₄OS requires 452. 30 5-Cl,6-F Found MH⁺ 487. C₂₄H₂₁ ³⁵ClF₂N₄OS requires 486. 31 4-Me Found MH⁺ 449. C₂₅H₂₅FN₄OS requires 448. 32 4,6-di-F Found MH⁺ 471. C₂₄H₂₁F₃N₄OS requires 470. 33 4-CH₂NMe₂ Found MH⁺ 492. C₂₇H₃₀FN₅OS requires 491. 34 5-Br Found MH⁺ 513. C₂₄H₂₂ ⁷⁹BrFN₄OS requires 512.

EXAMPLE 35 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

A solution of 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (700 mg, 3.0 mmol), HATU (1.12 g, 3.0 mmol) and N,N-diisopropylethylamine (1.54 ml, 9.0 mmol) in DMF (20 ml) was stirred at room temperature under argon for 2 min. The mixture was then treated with (RS)-5,6-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D18 (742 mg, 3.0 mmol) and stirring was continued for 16 h. The solvent was removed in vacuo and the residue partitioned between water and ethyl acetate. The organic phase was dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 0-5% methanol-ethyl acetate) afforded the title compound as a pale yellow solid (1.35 g, 97%).

Mass spectrum (Electrospray LC/MS): Found 471 (MH⁺). C₂₄H₂₁F₃N₄OS requires 470

¹H NMR δ: 0.80-1.90 (6H+H₂O, bm), 2.71 and 2.75 (3H, 2 Xs), 3.04 (1H, dt, J=3 and 13 Hz), 3.17 (0.8H, dd, J=5 and 13 Hz), 3.42-3.58 (1.8H, bm), 3.74 (0.2H, m), 4.43 (0.4H, m), 5.35 (1H, 0.8H, m), 6.75 (1.6H, t, J=8 Hz), 7.00-7.20 (3H, bm), 7.40-7.57 (1.4H, m), 11.30 and 12.38 (1H, 2 Xbs).

The title compound (900 mg) was dissolved in methanol and treated with 1M HCl in diethyl ether (excess). The volatiles were removed in vacuo and the residue was triturated with ethyl acetate to give a white solid (805 mg). A sample (450 mg) was crystallised form ethyl acetate to give the hydrochloride salt of the title compound as white solid (420 mg). Mass spectrum (Electrospray LC/MS) Found 471. C₂₄H₂₁F₃N₄OS requires 470.

EXAMPLE 36 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

A solution of 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (1.00 g, 4.2 mmol), HATU (1.60 g, 4.2 mmol) and N,N-diisopropylethylamine (2.00 ml, 11.6 mmol) in DMF (20 ml) was stirred at room temperature under argon for 2 min. The mixture was then treated with (RS)-4,5-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D21 (1.06 g, 4.2 mmol) and stirring was continued for 16 h. The solvent was removed in vacuo and the residue was washed with water then was triturated with ethyl acetate to afford the title compound as an off-white solid (1.68 g, 85%).

Mass spectrum (Electrospray LC/MS): Found 471 (MH⁺). C₂₄H₂₁F₃N₄OS requires 470.

The title compound (650 mg) was dissolved in methanol and treated with 1M HCl in diethyl ether (excess). The volatiles were removed in vacuo and the residue was triturated with ethyl acetate to afford the hydrochloride salt of the title compound as a white solid (615 mg). Mass spectrum (Electrospray LC/MS) Found 471 (MH⁺). C₂₄H₂₁F₃N₄OS requires 470.

EXAMPLE 37 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone

A stirring solution of 5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazole-4-carboxylic acid (632 mg, 2.0 mmol, 80% pure), EDC.HCl (311 mg, 2.0 mmol) and 1-hydroxybenzotriazole (270 mg, 2.0 mmol) in DMF (20 ml) was treated with (RS)-5,6-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D18 (500 mg, 2.0 mmol). The reaction mixture was stirred at room temperature, under argon for 16 h. The DMF was removed in vacuo and the residue was partitioned between ethyl acetate and water. The organic phase was dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 0-10% methanol-ethyl acetate) afforded the title compound as a pale yellow solid (350 mg, 36%).

Mass spectrum (Electrospray LC/MS): Found 487 (MH⁺). C₂₄H₂₁F₃N₄O₂S requires 486.

¹H NMR (DMSO-d₆) δ: 0.90-1.80 (6H, bm), 2.92-3.30 (3H+DMSO, bm), 4.15 (0.4H, m), 4.40-4.60 (1H, bm), 4.73 (1H, d, J=9 Hz), 5.30 (0.6H, m), 6.20 (1H, m), 7.05-7.65 (6H, bm), 12.24 and 12.56 (1H, 2 Xbs).

The title compound (350 mg) was dissolved in methanol and treated with 1M HCl in diethyl ether (excess). The volatiles were removed in vacuo and the residue was triturated with EtOAc to afford the hydrochloride salt of the title compound as a white solid (215 mg). Mass spectrum (Electrospray LC/MS) Found 487 (MH⁺). C₂₄H₂₁F₃N₄O₂S requires 486.

EXAMPLE 38 (RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone

A stirring solution of 5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazole-4-carboxylic acid (320 mg, 1.0 mmol, 80% pure) and (RS)-4,5-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D21 (250 mg, 1.0 mmol) in DMF (10 ml) was treated with EDC.HCl (194 mg, 1.0 mmol) and 1-hydroxybenzotriazole (50 mg, 0.4 mmol). The reaction mixture was stirred at room temperature, under argon for 16 h. The resulting solution was diluted with diethyl ether then washed with saturated aqueous NaHCO₃, water (3×) and brine. Drying (MgSO₄) and removal of the solvent in vacuo afforded an orange gum. Chromatography (silica gel, 0-2% methanol-dichloromethane) afforded the title compound as an orange powder (160 mg, 33%).

Mass spectrum (Electrospray LC/MS) Found 487 (MH⁺). C₂₄H₂₁F₃N₄O₂S requires 486.

The title compound (80 mg) was dissolved in methanol and treated with 1M HCl in diethyl ether (excess). The volatiles were removed in vacuo and the residue was triturated with diethyl ether to afford the hydrochloride salt of the title compound as a pale orange solid (65 mg).

Mass spectrum (Electrospray LC/MS): Found 487 (MH⁺). C₂₄H₂₁F₃N₄O₂S requires 486.

EXAMPLE 39 (RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone

A solution of 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (73 mg, 0.33 mmol), HATU (124 mg, 0.33 mmol) and N,N-diisopropylethylamine (0.35 ml) in DMF (6 ml) was stirred at room temperature under argon for 0.5 h. The mixture was then treated with (RS)-5,6-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole. 2HCl, D₂O (105 mg, 0.33 mmol) and stirring, under argon was continued for 16 h. The reaction mixture was diluted with diethyl ether and washed with water (3×), dried (MgSO₄) and the solvent removed in vacuo. Chromatography (silica gel, ethyl acetate) afforded the title compound (88 mg, 57%).

Mass spectrum (Electrospray LC/MS): Found 454 (MH⁺). C₂₄H₂₂F₃N₅O requires 453.

EXAMPLE 40 (RS)-1-[2-(5-Methoxy-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

A stirring mixture of (1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-acetic acid, D17 (150 mg, 0.42 mmol) and 4-methoxy-benzene-1,2-diamine (58 mg, 0.42 mmol) was heated at 120° C. for 4 h. The cooled reaction mixture was dissolved in ethyl acetate, washed with sodium hydrogen carbonate (2×) then brine. The solvent was removed in vacuo and the residue was chromatographed (silica gel, ethyl acetate) to afford the title compound as a brown gum (25 mg, 13%).

Mass spectrum (Electrospray LC/MS): Found 465 (MH⁺). C₂₅H₂₅FN₄O₂S requires 464.

The compounds of the Examples 41-50 and 92-108 were prepared from the appropriate carboxylic acid or acid chloride and (RS)-4,5-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D21 using a similar procedure to that described in Example 2 or a procedure similar to that described in Examples 1 or 4. The compounds of Examples 47, 48 and 49 were converted to hydrochloride salts by treatment with 1 M HCl in diethyl ether. The compound of Example 96 was prepared as the trifluoroacetate salt.

TABLE 3

Mass Spectrum (Electrospray Example Ar² Method LC/MS) 41

E2 Found MH⁺ 453. C₂₄H₂₂F₂N₄OSrequires 452. 42

E2 Found MH⁺ 454. C₂₄H₂₂F₃N₅Orequires 453. 43

E2 Found MH⁺ 440. C₂₃H₂₀F₃N₅Orequires 439. 44

E2 Found MH⁺ 540. C₂₈H₃₁F₂N₅O₂Srequires 539. 45

E4 Found MH⁺ 471. C₂₄H₂₁F₃N₄OSrequires 470. 46

E4 Found MH⁺ 471. C₂₄H₂₁F₃N₄OSrequires 470. 47

E2 Found MH⁺ 440. C₂₁H₁₈F₅N₃O₂requires 439. 48

E2 Found MH⁺ 400. C₂₂H₂₃F₂N₃O₂requires 399. 49

E2 Found MH⁺ 416. C₂₂H₂₃F₂N₃Orequires 415. 50

E2 Found MH⁺ 422. C₂₃H₂₁F₂N₅Orequires 421. 92

E2 Found MH⁺ 437. C₂₄H₂₂F₂N₄O₂requires 436. 93

E2 Found MH⁺ 505.C₂₄H₂₀ ³⁵Cl₂F₂N₄O₂requires 504. 94

E2 Found MH⁺ 454. C₂₄H₂₂F₃N₅Orequires 453 95

E1 Found MH⁺ 489. C₂₄H₂₀ ³⁵ClF₃N₄O₂requires 488. 96

E2 Found MH⁺ 471. C₂₄H₂₁ ³⁵ClF₂N₄O₂requires 470. 97

E2 Found MH⁺ 414. C₂₃H₂₅F₂N₃O₂requires 413. 98

E2 Found MH⁺ 414. C₂₃H₂₅F₂N₃O₂requires 413. 99

E2 Found MH⁺ 462. C₂₇H₂₅F₂N₃O₂requires 461. 100

E2 Found MH⁺ 430. C₂₃H₂₅F₂N₃O₃requires 429. 101

E2 Found MH⁺ 414. C₂₃H₂₅F₂N₃O₂requires 413. 102

E2 Found MH⁺ 444. C₂₄H₂₇F₂N₃O₃requires 443. 103

E2 Found MH⁺ 442. C₂₄H₂₅F₂N₃O₃requires 441. 104

E2 Found MH⁺ 450. C₂₆H₂₅F₂N₃O₂requires 449. 105

E2 Found MH⁺ 433. C₂₅H₂₂F₂N₄Orequires 432. 106

E2 Found MH⁺ 421. C₂₄H₂₂F₂N₄Orequires 420. 107

E2 Found MH⁺ 554. C₂₉H₃₃F₂N₅O₂Srequires 553. 108

E2 Found MH⁺ 568. C₃₀H₃₅F₂N₅O₂Srequires 567.

The compounds of the Examples 51-55 and 109-112 in Table 4 were prepared from the appropriate carboxylic acid and (RS)-5,6-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D18 using a similar procedure to that described in Example 2 or Example 4 or from the appropriate acid chloride and (RS)-5,6-difluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D18 using a procedure similar to that described for Example 1. The compound of Example 55 was converted to the hydrochloride salt by treatment with 1M HCl in diethyl ether. The compound of Example 109 was prepared as the trifluoroacetate salt.

TABLE 4

Mass Spectrum (Electrospray Example Ar² Method LC/MS) 51

E2 Found MH⁺ 440. C₂₃H₂₀F₃N₅Orequires 439. 52

E2 Found MH⁺ 438. C₂₃H₂₁F₂N₅O₂requires 437 53

E2 Found MH⁺ 511. C₂₇H₂₉F₃N₆Orequires 510 54

E2 Found MH⁺ 455. C₂₃H₂₁F₃N₆Orequires 454 55

E1 Found MH⁺ 539. C₂₉H₃₂F₂N₄O₂Srequires 538. 109

E4 Found MH⁺ 487. C₂₄H₂₁F₃N₄O₂Srequires 486. 110

E2 Found MH⁺ 485. C₂₅H₂₃F₃N₄OSrequires 484. 111

E4 Found MH⁺ 471. C₂₄H₂₁F₃N₄OSrequires 470. 112

E4 Found MH⁺ 471. C₂₄H₂₁F₃N₄OSrequires 470.

EXAMPLE 56 (RS)-1-[2-(5,6-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E35 (400 mg, 0.85 mmol) was slowly added to an ice-cooled slurry of NaH (68 mg, 60% dispersion on mineral oil, 1.7 mmol) in DMF (10 ml). After 0.5 h iodomethane (0.90 mmol) was added. The reaction mixture was stirred at room temperature, under argon for 16 h. 2N HCl (9 drops) then water (100 ml) were added. The aqueous phase was extracted with EtOAc(2×) and the combined organics washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. The residue was chromatographed (silica gel, 50-100% pentane-ethyl acetate). Residual DMF was removed by dissolving in ethyl acetate/diethyl ether and washing with water (2×). Drying (Na₂SO₄) and removal of the solvent in vacuo afforded the title compound as a pale yellow solid (142 mg, 34%).

Mass spectrum (Electrospray LC/MS): Found 485 (MH⁺). C₂₅H₂₃F₃N₄OS requires 484.

EXAMPLE 57 1-[(S)-2-(1H-Benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound was prepared from (S)-pyrrolidin-2-ylmethyl-1H-benzoimidazole, D26 and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid by a procedure similar to that described for Example 2. Chromatography (silica gel, 0-8%[10% 0.880 NH₃ in MeOH] in dichloromethane) afforded the title compound as a brown gum.

Mass spectrum (API⁺): found 421 (MH⁺). C₂₃H₂₁N₄OS requires 420.

EXAMPLE 58 1-[(S)-2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound was prepared from, (S)-5,6-difluoro-pyrrolidin-2-ylmethyl-1H-benzoimidazole, D27 and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid by a procedure similar to that described for Example 1. Chromatography (silica gel, 0-8%[10% 0.880 NH₃ in methanol] in dichloromethane) afforded the title compound as a beige solid.

Mass spectrum (API⁺): found 457 (MH⁺). C₂₃H₁₉F₃N₄OS requires 456.

EXAMPLE 59 1-[(S)-2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-1-[4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]methanone

The title compound was prepared from, (S)-5,6-difluoro-pyrrolidin-2-ylmethyl-1H-benzoimidazole, D27 and 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid by a procedure similar to that described for Example 2. Chromatography (silica gel, 0→8%[10% 0.880 NH₃ in methanol] in dichloromethane) afforded the title compound as a beige solid.

Mass spectrum (API⁺): found 440 (MH⁺): C₂₃H₂₀F₃N₅O requires 439.

EXAMPLE 60 (RS)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]-methanone

2-Piperidin-2-ylmethylbenzothiazole, D30 (0.135 g), HATU (0.228 g), diisopropylethylamine (0.300 ml) and 5-(4-fluorophenyl)-2-methylthiazol-4-carboxylic acid (0.144 g) were dissolved in dry DMF and shaken at room temperature for 16 hours. The solvent was then evaporated and the residue partitioned between dichloromethane and brine. The organic layer was dried (MgSO₄), evaporated and the residue chromatographed over silica gel. Elution with diethyl ether provided the title compound as a foam (220 mg).

Mass spectrum (API⁺): found 452 (MH⁺): C₂₄H₂₂FN₃OS₂ requires 451.

EXAMPLE 61 (RS)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-1-[4-(4-fluorophenyl)-1-methyl-1-H-pyrazol-3-yl]-methanone

The title compound (0.210 g) was prepared from 2-piperidin-2-ylmethyl-benzothiazole, D30 (0.135 g) and 4-(4-fluorophenyl)-1-methyl-1-H-pyrazol-3-carboxylic acid (0.135 g) using the procedure described in Example 60.

Mass spectrum (API⁺): found 435 (MH⁺): C₂₄H₂₃FN₄OS requires 434.

EXAMPLE 62 (RS)-1-(2-Benzothiazol-2-ylmethylpiperidin-1-yl)-1-[2-(3-methyl-[1,2,4]oxadiazol-5-yl)phenyl]-methanone

The title compound (0.170 g) was prepared from 2-piperidin-2-ylmethyl-benzothiazole, D30 (0.135 g), and 2-(3-methyl-[1,2,4]oxadiazol-5-yl)benzoic acid (0.126 g) using the procedure described in Example 60.

Mass spectrum (API⁺): found 419 (MH⁺): C₂₃H₂₂N₄O₂S requires 418.

EXAMPLE 63 AND EXAMPLE 64 (RS)-1-[5-(4-Fluorophenyl)-2-methylthiazol-4-yl]-1-[2-(5,6,7,8-tetrahydro-[1,2,4]-triazolo[1,5-a]pyridin-2-ylmethyl)-piperidin-1-yl]-methanone and (RS)-1-[5-(4-Fluorophenyl)-2-methylthiazol-4-yl]-1-(2-[1,2,4]triazolo[1,5-a]pyridin-2-ylmethylpiperidin-1-yl)-methanone

The mixture of 2-piperidin-2-ylmethyl-5,6,7,8-tetrahydro-[1,2,4]-triazolo[1,5-a]pyridine and 2-piperidin-2-ylmethyl-[1,2,4]-triazolo[1,5-a]pyridine, D34 (0.220 g) was treated with HATU (0.380 g), N,N-diisopropylethylamine (1.0 ml) and 5-(4-fluorophenyl)-2-methylthiazole-4-carboxylic acid (0.240 g) in dry DMF, according to the procedure described in Example 60. The crude product was chromatographed (silica gel, 4% methanol-diethyl ether) to afford 1-[5-(4-fluoro-phenyl)-2-methylthiazol-4-yl]-1-(2-[1,2,4]-triazolo[1,5-a]pyridin-2-ylmethylpiperidin-1-yl)-methanone as a colourless foam (0.070 g) (Mass spectrum (API⁺): found 436 (MH⁺): C₂₃H₂₂FN₅OS requires 435). Continued elution (10% methanol-diethyl ether) afforded 1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-[2-(5,6,7,8-tetrahydro-[1,2,4]-triazolo[1,5-a]pyridin-2-ylmethyl)-piperidin-1-yl]-methanone as a colourless foam (0.230 g)

(Mass spectrum (API⁺): found 440 (MH⁺): C₂₃H₂₆FN₅OS requires 439).

EXAMPLE 65a AND b 1-[(RS)-2-((RS)-2-Benzofuran-2-yl-2-hydroxy-ethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone (as separate diastereoisomers)

A solution of (RS)-1-Benzofuran-2-yl-2-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-yl)-ethanone, D38 (50 mg, 0.11 mmol) in methanol was treated with sodium borohydride (50 mg). The reaction mixture was stirred at room temperature, under argon for 16 h. The volatiles were removed in vacuo and the residue was triturated with dichloromethane. The dichloromethane soluble material was chromatographed (silica gel, diethyl ether) to afford, separately the two diastereoisomers of the title compound.

Mass spectrum (API⁺): found 447 (MH⁺-H₂O): C₂₆H₂₅FN₂O₃S requires 464 (first eluting diastereoisomer).

Mass spectrum (API⁺): found 447 (MH⁺-H₂O): C₂₆H₂₅FN₂O₃S requires 464 (second eluting diastereoisomer)

EXAMPLE 66 (RS)-1-[2-(4-Bromo-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone

2-Methyl-5-(4-fluorophenyl)thiazole-4-carbonyl chloride (383 mg, 1.5 mmol) was added portionwise over 5 min. to a stirred solution of (RS)-4-bromo-2-piperidin-2-ylmethyl-1H-benzoimidazole, D39 (400 mg, 1.4 mmol) and triethylamine (0.57 ml, 5.0 mmol) in dichloromethane (20 ml) at room temperature. After 20 h the mixture was washed with saturated sodium hydrogen carbonate. The organic layer was dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 10-100% ethyl acetate-hexane then 1-10% methanol-ethyl acetate) afforded the title compound as a pale brown amorphous solid (620 mg, 89%).

Mass spectrum (Electrospray LC/MS): Found 513 (MH⁺). C₂₄H₂₂ ⁷⁹BrFN₄OS requires 512.

EXAMPLE 67 (RS)-1-[2-(4-Cyano-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone

A mixture of (RS)-1-[2-(4-bromo-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone, E66 (216 mg, 0.42 mmol) and copper(I)cyanide (76 mg, 0.84 mmol) in N-methylpyrrolidinone (15 ml) was heated at reflux for 3 h. The reaction mixture was cooled, poured into water and extracted with ethyl acetate (2×). Solid sodium chloride was added to the aqueous layer which was further extracted with ethyl acetate (2×). The combined organic extracts were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. The residue was Chromatographed (silica gel, 10-100% ethyl acetate-hexane then 1-20% methanol-ethyl acetate). Further purification by HPLC (Supercosil ABZ⁺, 5-95% acetonitrile containing 0.1% trifluoroacetic acid-water containing 0.1% trifluoroacetic acid) afforded the title compound as a pale brown amorphous solid (5.3 mg, 3%).

Mass spectrum (Electrospray LC/MS): Found 460 (MH⁺). C₂₅H₂₂FN₅OS requires 459.

EXAMPLE 68 (RS)-1-[2-(4-Acetyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone

To a deoxygenated solution of (RS)-1-[2-(4-bromo-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone, E66 (200 mg, 0.39 mmol) in anhydrous 1,4-dioxane (10 ml) was added tributyl(1-ethoxyvinyl)tin (155 mg, 0.43 mmol) and tetrakis(triphenylphosphine)palladium(0) (30 mg, 0.026 mmol). The resultant mixture was refluxed under argon for 20 h. Further tetrakis(triphenylphosphine)palladium(0) (60 mg, 0.052 mmol) was added and refluxing continued for a further 24 h. On cooling, water (15 ml) and 5N hydrochloric acid (10 drops) were added and the mixture stirred at room temperature for 2 h. The reaction mixture was poured into water and extracted with ethyl acetate (3×). The combined organics were dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel,

0-100% ethyl acetate-hexane then 2-5% methanol-ethyl acetate) afforded the title compound as a pale orange solid (62 mg, 33%).

Mass spectrum (Electrospray LC/MS): Found 475 (M-H). C₂₆H₂₅FN₄O₂S requires 476.

EXAMPLE 69 (RS)-2-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-ylmethyl)-1H-benzoimidazole-5-carbonitrile

A stirring mixture of (RS)-1-[2-(5-bromo-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E34 (25 mg, 0.44 mmol) and copper(I)cyanide (79 mg, 0.88 mmol) in N-methylpyrrolidinone (7 ml) under argon was heated at 200° C. for 5 h. The cooled reaction mixture was diluted with water/ethyl acetate and filtered through Kieselghur. The organic phase was washed with water (2×), brine (2×), dried (MgSO₄) and the solvent removed in vacuo. The residue was chromatographed (silica gel, 0-4% methanol (containing 10%.0.880 ammonia)-dichloromethane). Further purification by HPLC (Supercosil ABZ⁺, 5-95% acetonitrile containing 0.1% trifluoroacetic acid-water containing 0.1% trifluoroacetic acid) afforded the title compound as a pale brown gum (2 mg, 1%).

Mass spectrum (Electrospray LC/MS): Found 460 (MH⁺). C₂₅H₂₂FN₅OS requires 459.

EXAMPLE 70 (RS)-1-[2-(5,6-Difluoro-1-propyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E35 (150 mg, 0.32 mmol) was added slowly to an ice-cooled slurry of sodium hydride (26 mg, 0.64 mmol, 60% dispersion in mineral oil) in DMF (10 ml). After stirring for a further 0.5 h, 1-iodopropane (60 mg, 0.35 mmol) was added. The mixture was stirred at room temperature for 16 h then partitioned between water and ethyl acetate. The organic phase was washed with water, brine, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 50-100% ethyl acetate-pentane then 0-5% methanol-ethyl acetate) afforded the title compound as a white solid.

Mass spectrum (Electrospray LC/MS): Found 513 (MH⁺). C₂₇H₂₇F₃N₄OS requires 512.

The product was dissolved in methanol and treated with 1M HCl in diethyl ether (excess). The volatiles were removed in vacuo to afford the hydrochloride salt of the title compound as pale green solid (170 mg).

Mass spectrum (Electrospray LC/MS): Found 513. C₂₇H₂₇F₃N₄OS requires 512.

EXAMPLE 71 (RS)-1-{2-[5,6-Difluoro-1-(2-methoxy-ethyl)-1H-benzoimidazol-2-ylmethyl]-piperidin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E35 (300 mg, 0.64 mmol) was added slowly to an ice-cooled slurry of sodium hydride (51 mg, 1.3 mmol, 60% dispersion in mineral oil) in DMF (10 ml). After stirring for 0.5 h 1-bromo-2-methoxy-ethane (139 mg, 10 mmol), N,N-diisopropylethylamine (0.3 ml) and potassium iodide (5 mg) was added. The mixture was stirred at room temperature for 0.5 h then 100° C. for 16 h. The volatiles were removed in vacuo from the cooled reaction mixture. The residue was partitioned between ethyl acetate and water. The aqueous phase was extracted with ethyl acetate (2×). The combined organics were dried (Na₂SO₄) and the solvent removed in vacuo. The residue was triturated with ethyl acetate to afford the title compound as a solid (306 mg, 65%).

Mass spectrum (Electrospray LC/MS) Found 529 (MH⁺). C₂₇H₂₇F₃N₄O₂S requires 528.

The product was dissolved in methanol and treated with 1M HCl in diethyl ether (excess). The volatiles were removed in vacuo and the residue triturated with methanol-ethyl acetate to afford the hydrochloride salt of the title compound as a white solid (66 mg).

Mass spectrum (Electrospray LC/MS): Found 529 (MH⁺). C₂₇H₂₇F₃N₄O₂S requires 528.

EXAMPLE 72 (RS)-1-{2-[1-(2-Dimethylamino-ethyl)-5,6-difluoro-1H-benzoimidazol-2-ylmethyl]-piperidin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound was prepared from (RS)-1-[2-(5,6-difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E35 (300 mg) and (2-chloro-ethyl)-dimethyl-amine, according to a procedure similar to that described for Example 71 as a white solid (88 mg, 26%).

Mass spectrum (Electrospray LC/MS): Found 542 (MH⁺). C₂₈H₃₀F₃N₅OS requires 541.

The hydrochloride salt of the title compound was prepared as described for E71

Mass spectrum (Electrospray LC/MS): Found 542 (MH⁺). C₂₈H₃₀F₃N₅OS requires 541.

EXAMPLE 73 (RS)-1-{2-[5,6-difluoro-1-(2-hydroxy-ethyl)-1H-benzoimidazol-2-ylmethyl]-piperidin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E35 (250 mg, 0.53 mmol) was added slowly to an ice-cooled slurry of sodium hydride (43 mg, 1.1 mmol, 60% dispersion in mineral oil) in DMF (10 ml), under argon. After stirring for a further 0.5 h, 2-bromoethanol (0.045 ml, 0.64 mmol) was added. The mixture was heated at 110° C. for 48 h, but only a minor amount of product had formed (MS). Potassium carbonate (1.00 g), N,N-diisopropylethylamine (1.0 ml) and a further portion of 2-bromoethanol (0.5 ml) were added and heating was continued for 16 h. The volatiles were removed in vacuo from the cooled reaction mixture. The residue was partitioned between ethyl acetate and water. The organic phase was dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 0-5% methanol-ethyl acetate) afforded the title compound as a white solid (78 mg, 29%).

Mass spectrum (Electrospray LC/MS): Found 515 (MH⁺). C₂₆H₂₅F₃N₄O₂S requires 514.

EXAMPLE 74 AND EXAMPLE 75 (RS)-1-[2-(6,7-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone and (RS)-1-[2-(4,5-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-1-[2-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E36 (400 mg, 0.85 mmol) was added slowly to an ice-cooled slurry of sodium hydride (68 mg, 1.7 mmol, 60% dispersion in mineral oil) in DMF (10 ml). After stirring for a further 0.5 h, iodomethane (266 mg, 0.87 mmol) was added. The mixture was stirred at room temperature for 72 h then partitioned between water and ethyl acetate. The organic phase was washed with water, brine, dried (Na₂SO₄) and the solvent removed in vacuo. Purification by HPLC (Supercosil ABZ⁺, 5-95% acetonitrile containing 0.1% trifluoroacetic acid-water containing 0.1% trifluoroacetic acid) afforded the title compounds (structures assignment based on nOe experiments): 1-[2-(6,7-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone (76 mg)

Mass spectrum (Electrospray LC/MS): Found 485 (MH⁺). C₂₅H₂₃F₃N₄OS requires 484.

¹H NMR δ: 0.75-1.85 (6H, bm), 2.42 and 2.72 (3H, s), 0.85-3.15 (2H, bm), 3.30 (1H, m), 3.42 (0.7H, m), 3.70 and 4.15 (3H, s), 4.25 (0.3H, m), 4.75 (0.3H, m), 5.10 (0.7H, m), 7.00 (3H, m), 7.35 (3H, m).

1-[2-(4,5-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone (106 mg)

Mass spectrum (Electrospray LC/MS): Found 485 (MH⁺). C₂₅H₂₃F₃N₄OS requires 484.

¹H NMR δ: 0.75-1.90 (6H, bm), 2.25 and 2.70 (3H, s), 2.9-3.2 (2H, bm), 3.15-3.45 (1.7H, bm), 3.56 and 3.94 (3H, s), 4.25 (0.3H, m), 4.76 (0.3H, m), 5.09 (0.7H, m), 6.98 (3H, m), 7.08 (1H, m), 7.36 (2H, m).

EXAMPLE 76 (RS)-2-(1-{1-[5-(4-Fluorophenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-ylmethyl)-benzofuran-3-carboxylic acid amide

To a solution of (RS)-2-(1-(2,2,2-trifluoro-ethanoyl)-piperidin-2-yl-methyl)-benzofuran-3-carbonitrile, D42 (480 mg, 1.4 mmol) in methanol (15 ml) and water (3 ml) was added potassium carbonate (700 mg, 4.9 mmol) and the mixture heated at reflux for 1.25 h. The solvent was removed in vacuo and the residue was partitioned between dichloromethane and water and basified to pH14. The aqueous phase was re-extracted with dichloromethane (3×). The combined organics were dried (Na₂SO₄) and the solvent removed in vacuo to afford a solid (0.34 g, 99%). To a portion of this material (67 mg, 0.28 mmol) in dichloromethane was added 5-(4-fluorophenyl)-2-methyl-thiazole-4-carboxylic acid (73 mg, 0.30 mmol), EDC.HCl (60 mg, 0.30 mml) and 1-hydroxybenzotriazole (10 mg). After 16 h at room temperature the reaction mixture was washed with saturated aqueous sodium hydrogen carbonate and the organic phase applied directly onto a pre-packed silica gel column. Elution with ethyl acetate-methanol mixtures afforded the title compound as an amorphous solid (8 mg, 6%).

Mass spectrum (Electrospray LC/MS): Found 478 (MH⁺). C₂₆H₂₄FN₃O₃S requires 477.

EXAMPLE 77 (RS)-2-(1-{1-[4-(4-Fluorophenyl)-1-methyl-1H-pyrazol-3-yl]-methanoyl}-piperidin-2-ylmethyl)-benzofuran-3-carboxylic acid amide

The title compound (7 mg, 5%), was prepared as described for E76 from (RS)-2-(1-(2,2,2-trifluoro-ethanoyl)-piperidin-2-yl-methyl)-benzofuran-3-carbonitrile, D42 and 4-(4-fluorophenyl)-1-methyl-1H-pyrazole carboxylic acid (61 mg, 0.3 mmol)

Mass spectrum (Electrospray LC/MS): Found 461 (MH⁺). C₂₆H₂₅FN₄O₃ requires 460.

EXAMPLE 78 (RS)-1-[3-(4,5-Difluoro-1H-benzoimidazol-2-ylmethyl)-morpholin-4-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (93 mg, 36%) was prepared from (4-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-morpholin-3-yl)-acetic acid, D45 according to the procedure described for Example 27.

Mass spectrum (Electrospray LC/MS): Found 473 (MH⁺). C₂₃H₁₉F₃N₄O₂S requires 472.

EXAMPLE 79 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-furo[3,2-b]-pyridin-2-ylmethyl-piperidin-1-yl)methanone

The title compound was prepared using the method of Example 4, from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (120 mg, 0.5 mmol) and (RS)-2-piperidin-2-ylmethyl-furo[3,2-b]pyridine, D47 (108 mg, 0.5 mmol), as a colourless solid (95 mg, 43%).

Mass spectrum (Electrospray LC/MS): Found 436 (MH⁺). C₂₄H₂₂FN₃O₂S requires 435.

EXAMPLE 80 (RS)-1-[4-(4-Fluoro-phenyl)-1-methyl-1H-pyrazole-3-yl)-(2-furo[3,2-b]pyridin-2-ylmethyl-piperidin-1-yl)methanone

The title compound was prepared using the method of Example 4, from 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (110 mg, 0.5 mmol) and (RS)-2-Piperidin-2-ylmethyl-furo[3,2-b]pyridine, D47 (108 mg, 0.5 mmol), as a colourless solid (130 mg, 62%).

Mass spectrum (Electrospray LC/MS): Found 419 (MH⁺). C₂₄H₂₃FN₄O₂ requires 418.

EXAMPLE 81 (RS)-1-[2-(3-Bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

To (RS)-2-(2-benzofuranylmethyl)-1-((5-(4-fluorophenyl)-2-methyl-thiazol-4-yl)-carbonyl)-piperidine, E1 (0.90 g, 2 mmol) in dry diethyl ether (10 ml) and dichloromethane (20 ml) cooled to −12° C. under argon, was added drop-wise a solution of bromine (0.36 g, 2 mmol) in dichloromethane (10 ml) over 0.5 h. The resulting solution was warmed to ambient temperature over 1.5 h, then stirred for a further 18 h. The reaction mixture was evaporated then re-evaporated from dichloromethane (3×). The resulting amorphous solid was chromatographed (silica gel with ethyl acetate-hexane mixtures) to afford the title compound as an amorphous solid (0.27 g, 25%).

Mass spectrum (Electrospray LC/MS) Found 513 (MH⁺). C₂₅H₂₂ ⁷⁹BrFN₂O₂S requires 512.

EXAMPLE 82 (RS)-2-(1-{1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-ylmethyl)-benzofuran-3-carbonitrile

To (RS)-1-[2-(3-bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E81 (270 mg, 0.53 mmol) in N-methyl-pyrrolidinone (8 ml) was added copper(I)cyanide (96 mg, 1.06 mmol) and the mixture stirred under argon at reflux for 6 h. The reaction mixture was cooled, poured into water (80 ml) and ethyl acetate (50 ml) and then filtered through kieselguhr. The filtrate was separated and the aqueous phase extracted with ethyl acetate (2×). The combined organics were washed with water (4×50 ml), dried and the solvent removed in vacuo. Chromatography (silica gel) afforded the title compound as a white amorphous solid (94 mg, 39%).

Mass spectrum (Electrospray LC/MS) Found 460 (MH⁺). C₂₆H₂₂FN₃O₂S requires 459.

EXAMPLE 83 (RS)-1-[2-(5-Fluorobenzofuran-2-ylmethyl)-4-methylpiperazin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone.hydrochloride

The title compound was prepared from (RS)-3-(5-fluorobenzofuran-2-ylmethyl)-1-methylpiperazine, D51 using the method of Example 1.

Mass spectrum (Electrospray LC/MS): Found 468 (MH⁺). C₂₅H₂₃F₂O₂S requires 467.

EXAMPLE 84 (RS)-1-(2-Benzofuran-2-ylmethyl-4-methyl-piperazin-1-yl)-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl)]-methanone

The title compound (0.53 g, 32%) was obtained from (RS)-3-benzofuran-2-ylmethyl-1-methyl-piperazine, D56 (0.89 g, 3.8 mmol) using the method of Example 1.

Mass spectrum (Electrospray LC/MS): Found 450 (MH⁺). C₂₅H₂₄FN₃O₂S requires 449.

EXAMPLE 85 (RS)-1-(2-Benzofuran-2-ylmethyl-piperazin-1-yl)-1-[5-(4-fluorophenyl)-2-methyl-thiazol-4-yl]-methanone.hydrochloride

To (RS)-1-(2-benzofuran-2-ylmethyl-4-methyl-piperazin-1-yl)-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl)]-methanone, E84 (0.45 g, 1 mmol) in 1,2-dichloroethane (10 ml) under argon at 0° C. was added N,N-diisopropylethylamine (0.52 ml, 3 mmol) followed by dropwise addition of 1-chloroethylchloroformate (0.77 ml, 6 mmol) over 1-2 min. After 5 min, the reaction mixture was warmed to ambient temperature over 0.5 h, and then heated at 65° C. for 4.5 h. Additional N,N-diisopropylethylamine (0.52 ml, 3 mmol) was added and heating continued for a further 2 h. The reaction was cooled and evaporated, and the residue refluxed in methanol (25 ml) for 2.5 h. The cooled reaction was evaporated and partitioned between dichloromethane (50 ml) and saturated aqueous sodium bicarbonate (25 ml), aqueous phase extracted with dichloromethane (2×25 ml). The combined organic extracts were dried (Na₂SO₄), evaporated and the residue chromatographed on silica gel eluting with methanol ethyl acetate mixtures to afford the free-base of the title compound (0.23 g, 52%). A sample was converted to the hydrochloride salt by dissolving in methanol/dichloromethane and treating with excess 1M HCl in diethyl ether. Removal of the solvent in vacuo afforded the title compound as an amorphous solid.

Mass spectrum (Electrospray LC/MS): Found 458 (MNa⁺). C₂₄H₂₂FN₃O₂S requires 435.

EXAMPLE 86 1-{(RS)-2-[(RS)-1-(5-Fluoro-benzofurany-2-yl)-1-hydroxy-methyl]-4-methyl-piperazin-1-yl}-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (0.043 g, 59%) was obtained from (RS)-1-(5-fluoro-benzofuran-2-yl)-1-((RS)-4-methyl-piperazin-2-yl)-methanol, D57 and 5-(4-(fluorophenyl)-2-methyl-thiazole-4-carbonyl chloride (0.043 g, 0.16 mmol) using the method of Example 1.

Mass spectrum (Electrospray LC/MS): Found 506 (MNa⁺). C₂₅H₂₃F₂N₃O₃S requires 483.

EXAMPLE 87 1-{(RS)-2-[(RS)-1-(5-Fluoro-benzofurany-2-yl)-1-hydroxy-methyl]-4-methyl-piperazin-1-yl}-1-(2-trifluoromethoxy-phenyl)-methanone

The title compound (0.034 g, 50%) was obtained from (RS)-1-(5-fluoro-benzofuran-2-yl)-1-((RS)-4-methyl-piperizan-2-yl)-methanol, D57 and 2-(trifluoromethoxy)benzoyl chloride using the method of Example 1.

Mass spectrum (Electrospray LC/MS): Found 453 (MH⁺). C₂₂H₂₀F₄N₂O₄ requires 452.

EXAMPLE 88 (RS)-1-[2-(1-{1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanoyl}-piperidin-2-ylmethyl)-benzofuran-3-yl]-ethanone

The title compound (120 mg, 41%) was obtained from (RS)-1-[2-(3-bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E81 (320 mg, 0.62 mmol) using the method of Example 68.

Mass spectrum (Electrospray LC/MS): Found 477 (MH⁺). C₂₇H₂₅FN₂O₃S requires 476.

EXAMPLE 89a AND EXAMPLE 89b (R)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone and(S)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

(RS)-1-[2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone E35 (380 mg) was separated to give the title compounds (stereochemistry not assigned) on a Chiralpak AD column (250 mm×19 mm i.d.; 10 micron particle size); Mobile Phase: n-hexane, HiPerSiolv:ethanol, 99.7% v/v-100% v/v, Analar: triethylamine, Analar (90:10:0.25 v/v/v): pre-mixed: isocratic procedure; injecting at 2.5 ml at concentration of 20 mg/ml racemate in ethanol, 99.7% v/v-100% v/v, Analar. Faster eluting enantiomer (132 mg, >99.8% e.e.):

Mass spectrum (Electrospray LC/MS): Found 471 (MH⁺). C₂₄H₂₁F₃N₄OS requires 470

Slower eluting enantiomer (173 mg, >99.8% e.e.):

Mass spectrum (Electrospray LC/MS): Found 471 (MH⁺). C₂₄H₂₁F₃N₄OS requires 470

TABLE 5

Mass Spectrum (Electrospray Example Ar² Method LC/MS) 113

E2 Found MH⁺ 453.C₂₄H₂₂F₂N₄OSrequires 452. 114

E2 Found MH⁺ 436.C₂₄H₂₃F₂N₅Orequires 435. 115

E2 Found MH⁺ 422.C₂₃H₂₁F₂N₅Orequires 421. 116

E2 Found MH⁺ 436.C₂₄H₂₃F₂N₅Orequires 435. 117

E2 Found MH⁺ 382.C₂₂H₂₄FN₃O₂requires 381. 118

E4 Found M − 1 467.C₂₄H₂₂F₂N₄O₂Srequires 468.(API LC/MS) The compounds of Examples 113-118 were prepared from the appropriate carboxylic acid and (RS)-4-fluoro-2-piperidin-2-ylmethyl-1H-benzoimidazole, D58 using a procedure similar to that described in Example 2 or Example 4.

EXAMPLE 119 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-{2-[4-(1-hydroxy-ethyl)-1H-benzoimidazol-2-ylmethyl]-piperidin-1-yl}-methanone

Sodium borohydride (145 mg) was added portionwise over 2 min. to a cooled (0-10° C.) solution of (RS)-1-[2-(4-acetyl-1H-benzimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluorophenyl)-2-methylthiazol-4-yl]methanone, E68 (365 mg) in methanol (10 ml). After stirring for a further 2.5 h at room temperature, water (100 ml) was added and the mixture was extracted with dichloromethane (2×). The combined organics were dried (Na₂SO₄), evaporated and the residue chromatographed (silica gel, 0-100% ethyl acetate-hexane then 2-10% methanol-ethyl acetate) to afford the title compound as a solid (320 mg).

Mass spectrum (Electrospray LC/MS): Found 479 (MH⁺). C₂₆H₂₇FN₄O₂S requires 478.

EXAMPLE 120 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[5-(4-chloro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (100 mg) was prepared from (RS)-2-(2-benzofuranylmethyl)piperidine, D3 (64 mg) and 5-(4-chloro-phenyl)-2-methyl-thiazole-4-carboxylic acid (76 mg) by a procedure similar to that described for Example 2.

Mass spectrum (API LC/MS): Found 451 (MH⁺). C₂₅H₂₃ ³⁵ClN₂O₂S requires 450.

EXAMPLE 121 (RS)-1-[2-(3-Chloro-furo[3,2-b]pyridin-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

A solution of chlorine (28 mg) in dichloromethane (3 ml) was added to a cooled (−12° C.) solution (RS)-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-(2-furo[3,2-b]-pyridin-2-ylmethyl-piperidin-1-yl)methanone, E79 (170 mg) in dichloromethane (4 ml). After stirring at −12° C. for 0.5 h the reaction mixture was stirred at room temperature for 16 h then the solution was washed with saturated aqueous NaHCO₃, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 0-100% ethyl acetate-hexane then 0-10% methanol-ethyl acetate) afforded the title compound (24 mg).

Mass spectrum (Electrospray LC/MS): Found 470 (MH⁺). C₂₄H₂₁ ³⁵ClFN₃O₂S requires 469.

EXAMPLE 122 (RS)-1-[2-(5,6-Difluoro-1-methyl-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone

The title compound (15 mg) was prepared from 5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazole-4-carboxylic acid (84 mg) and (RS)-5,6-difluoro-1-methyl-2-piperidin-2-ylmethyl-1H-benzoimidazole, D61 (86 mg) by a procedure similar to that described for Example 4.

Mass spectrum (Electrospray LC/MS): Found 501 (MH⁺). C₂₅H₂₃F₃N₄O₂S requires 500.

EXAMPLE 123 (RS)-1-[2-(5-Chloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (135 mg) was prepared from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (211 mg) and 3-(5-Chloro-benzofuran-2-ylmethyl)-1-methyl-piperazine, D63 (200 mg) by a procedure similar to that described for Example 1.

Mass spectrum (API⁺LC/MS): Found 484 (MH⁺). C₂₅H₂₃ ³⁵ClFN₃O₂S requires 483

EXAMPLE 124 (RS)-1-[2-(5-Chloro-benzofuran-2-ylmethyl)-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound was prepared from 1-[2-(5-chloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E123 (95 mg) by a procedure similar to that described for Example 85.

Purification by HPLC (Supercosil ABZ⁺, 5-95% acetonitrile containing 0.1% trifluoroacetic acid-water containing 0.1% trifluoroacetic acid) afforded the title compound (5 mg) as the TFA salt.

Mass spectrum (Electrospray LC/MS): Found 470 (MH⁺). C₂₄H₂₁ ³⁵ClFN₃O₂S requires 469.

EXAMPLE 125 (RS)-1-[2-(5,7-Dichloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (80 mg) was prepared from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (498 mg) and (RS)-3-(5,7-dichloro-benzofuran-2-ylmethyl)-1-methyl-piperazine, D65 (530 mg) by a procedure similar to that described for Example 1.

Mass spectrum (API⁺LC/MS): Found 518 (MH⁺). C₂₅H₂₂ ³⁵Cl₂FN₃O₂S requires 517.

EXAMPLE 126 (RS)-1-[2-(5,7-Dichloro-benzofuran-2-ylmethyl)-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound was prepared from (RS)-1-[2-(5,7-dichloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone E125 (72 mg) by a procedure similar to that described for Example 85. Purification by HPLC (Supercosil ABZ⁺, 5-95% acetonitrile containing 0.1% trifluoroacetic acid-water containing 0.1% trifluoroacetic acid) afforded the title compound (6 mg) as the TFA salt.

Mass spectrum (Electrospray LC/MS): Found 504 (MH⁺). C₂₄H₂₀ ³⁵Cl₂FN₃O₂S requires 503.

EXAMPLE 127 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-[2-(1H-indol-2-ylmethyl)-piperidin-1-yl]-methanone

(RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-{2-[1-(2-trimethylsilanyl-ethoxymethyl)-1H-indol-2-ylmethyl]-piperidin-1-yl}-methanone (130 mg) was prepared from (RS)-2-piperidin-2-ylmethyl-1-(2-trimethylsilanyl-ethoxymethyl)-1H-indole, D68 (520 mg) and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (512 mg) according to a procedure similar to that for Example 1. A stirring solution of the above amide (125 mg) in dry THF (5 ml) was treated with a solution of tetrabutylammonium fluoride (2.2 mmol) in THF (5 ml). Once tlc indicated the reaction had gone to completion, the reaction mixture was poured into water and the product extracted with ethyl acetate. The combined organics were washed with brine, dried (Na₂SO₄) and the solvent removed in vacuo. Chromatography (silica gel, 0-100% pentane-ethyl acetate followed by preparative tlc, 40% ethyl acetate-pentane) afforded the title compound as a white solid (2.5 mg).

Mass spectrum (Electrospray LC/MS): Found 434 (MH⁺). C₂₅H₂₄FN₃OS requires 433.

EXAMPLE 128 (RS)-5-[1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-methanoyl]-4H-benzo[1,4]oxazin-3-one

The title compound (65 mg) was prepared from (RS)-2-(2-benzofuranylmethyl)piperidine, D3 (65 mg) and 3-oxo-3,4-dihydro-2H-benzo[1,4]oxazine-5-carboxylic acid (39 mg) by a procedure similar to that for Example 2.

Mass spectrum (Electrospray LC/MS): Found 391 (MH⁺). C₂₃H₂₂N₂O₄ requires 390.

EXAMPLE 129 (RS)-1-[2-(5-Bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (490 mg) was prepared from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (488 mg) and (RS)-2-(5-bromo-benzofuran-2-ylmethyl)-piperidine, D70 (530 mg) by a procedure similar to that described for Example 1.

Mass spectrum (Electrospray LC/MS): Found 513 (MH⁺). C₂₅H₂₂ ⁷⁹BrFN₂O₂S requires 512.

EXAMPLE 130 (RS)-1-[2-(5-Cyano-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (19 mg) was prepared from (RS)-1-[2-(5-bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E129 (420 mg) and copper(I)cyanide according to a procedure similar to that described for Example 67.

Mass spectrum (API⁺LC/MS): Found 460 (MH⁺). C₂₆H₂₂FN₃O₂S requires 459.

EXAMPLE 131 (RS)-1-[2-(4-Bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (0.45 g) was prepared from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (0.89 g) and 2-(4-bromo-benzofuran-2-ylmethyl)-piperidine, D72 (0.88 g) by a procedure similar to that described for Example 1.

Mass spectrum (Electrospray LC/MS): Found 513 (MH⁺). C₂₅H₂₂ ⁷⁹BrFN₂O₂S requires 512.

EXAMPLE 132 (RS)-1-[2-(4-Cyano-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (80 mg) was prepared from (RS)-1-[2-(4-bromo-benzofuran-2-ylmethyl)-piperidin-1-yl]1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E131 (400 mg) and copper(I)cyanide according to a procedure similar to that described for Example 67.

Mass spectrum (Electrospray LC/MS): Found 460 (MH⁺). C₂₆H₂₂FN₃O₂S requires 459.

EXAMPLE 133 (RS)-1-[5-(4-Fluoro-phenyl)-2-methyl-thiazol-4-yl]-1-[2-(3-methyl-benzofuran-2-ylmethyl)-piperidin-1-yl]-methanone

The title compound (18 mg) was prepared from (RS)-2-(3-methyl-benzofuran-2-ylmethyl)-piperidine, D74 (92 mg) and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (190 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (API LC/MS): Found 449 (MH⁺). C₂₆H₂₅FN₂O₂S requires 448.

EXAMPLE 134 (RS)-1-[2-(4-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (60 mg) was prepared from (RS)-2-(4-fluoro-benzofuran-2-ylmethyl)-piperidine, D76 (157 mg) and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (160 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (API LC/MS): Found 453 (MH⁺). C₂₅H₂₂F₂N₂O₂S requires 452.

EXAMPLE 135 (RS)-1-[2-(4-Fluoro-benzofuran-2-ylmethyl)-piperidin-1-yl]-1-[4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone

The title compound (45 mg) was prepared from (RS)-2-(4-fluoro-benzofuran-2-ylmethyl)-piperidine, D76 (157 mg) and 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (160 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (API LC/MS): Found 436 (MH⁺). C₂₅H₂₃F₂N₃O₂ requires 435.

EXAMPLE 136 (RS)-1-[2-(4,6-Dichloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (107 mg) was prepared from 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carbonyl chloride (241 mg) and 3-(4,6-dichloro-benzofuran-2-ylmethyl)-1-methyl-piperazine, D78 (263 mg) by a procedure similar to that described for Example 1.

Mass spectrum (Electrospray LC/MS): Found 518 (MH⁺). C₂₅H₂₂ ³⁵Cl₂FN₃O₂S requires 517.

EXAMPLE 137 (RS)-1-[2-(4,6-Dichloro-benzofuran-2-ylmethyl)-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound was prepared from (RS)-1-[2-(4,6-dichloro-benzofuran-2-ylmethyl)-4-methyl-piperazin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E136 (87 mg) by a procedure similar to that described for Example 85.

Purification by HPLC (Supercosil ABZ⁺, 5-95% acetonitrile containing 0.1% trifluoroacetic acid-water containing 0.1% trifluoroacetic acid) afforded the title compound (mg) as the TFA salt.

Mass spectrum (Electrospray LC/MS): Found 504 (MH⁺). C₂₄H₂₀ ³⁵Cl₂FN₃O₂S requires 503.

EXAMPLE 138 (RS)-1-(2-Benzofuran-2-ylmethyl-pyrrolidin-1-yl)-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (45 mg) was prepared from (RS)-2-benzofuran-2-ylmethyl-pyrrolidine D81 (114 mg) and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (147 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (Electrospray LC/MS): Found 421 (MH⁺). C₂₄H₂₁FN₂O₂S requires 420.

EXAMPLE 139 (RS)-1-(2-Benzofuran-2-ylmethyl-pyrrolidin-1-yl)-1-[4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone

The title compound (29 mg) was prepared from (RS)-2-benzofuran-2-ylmethyl-pyrrolidine D81 (114 mg) and 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (137 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (Electrospray LC/MS): Found 404 (MH⁺). C₂₄H₂₂FN₃O₂ requires 403.

EXAMPLE 140 (RS)-1-(2-Benzo[b]thiophen-2-ylmethyl-piperidin-1-yl)-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone

The title compound (40 mg) was prepared from 2-benzo[b]thiophen-2-ylmethyl-piperidine

D83 (133 mg) and 5-(4-fluoro-phenyl)-2-methyl-thiazole-4-carboxylic acid (136 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (Electrospray LC/MS): Found 451 (MH⁺). C₂₅H₂₃FN₂OS₂ requires 450.

EXAMPLE 141 (RS)-1-(2-Benzo[b]thiophen-2-ylmethyl-piperidin-1-yl)-1-[4-(4-fluoro-phenyl)-1-methyl-1H-pyrazol-3-yl]-methanone

The title compound (6 mg) was prepared from 2-benzo[b]thiophen-2-ylmethyl-piperidine D83 (133 mg) and 4-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid (140 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (Electrospray LC/MS): Found 434 (MH⁺). C₂₅H₂₄FN₃OS requires 433.

EXAMPLE 142 (RS)-1-(2-Benzo[b]thiophen-2-ylmethyl-piperidin-1-yl)-1-quinolin-8-yl-methanone

The title compound (4 mg) was prepared from 2-benzo[b]thiophen-2-ylmethyl-piperidine

D83 (133 mg) and 8-quinoline carboxylic acid (109 mg) according to a procedure similar to that described for Example 4.

Mass spectrum (Electrospray LC/MS): Found 387 (MH⁺). C₂₄H₂₂N₂OS requires 386

EXAMPLE 143 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-(2-methyl-5-phenyl-thiazol-4-yl)-methanone

The title compound (90 mg) was prepared from (RS)-2-(2-benzofuranylmethyl)piperidine, D3 (100 mg) and 5-phenyl-2-methyl-thiazole-4-carbonyl chloride (122 mg) according to a procedure similar to that for Example 1.

Mass spectrum (Electrospray LC/MS): Found 417 (MH⁺). C₂₅H₂₄N₂O₂S requires 416.

EXAMPLE 144 1-[(S)-2-(5,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-pyrrolidin-1-yl]-[5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazol-4-yl]-methanone

The title compound (65 mg) was prepared from 5,6-difluoro-2-(S)-1-pyrrolidin-2-ylmethyl-1H-benzoimidazole, D27 (153 mg) and 5-(4-fluoro-phenyl)-2-hydroxymethyl-thiazole-4-carboxylic acid (205 mg) according to a procedure similar to that for Example 4.

Mass spectrum (Electrospray LC/MS): Found 473 (MH⁺). C₂₃H₁₉F₃N₄O₂S requires 472.

EXAMPLE 145 (RS)-1-(2-Benzofuran-2-ylmethyl-piperidin-1-yl)-1-[2-(3-methyl-[1,2,4]oxadiazol-5-yl)-phenyl]-methanone

The title compound (33 mg) was prepared from (RS)-2-(2-benzofuranylmethyl)piperidine, D3 (108 mg) and 2-(3-methyl-[1,2,4]oxadiazol-5-yl)-benzoic acid (102 mg) according to a procedure similar to that for Example 2.

Mass spectrum (Electrospray LC/MS): Found 402 (MH⁺). C₂₄H₂₃N₃O₃ requires 401.

EXAMPLE 146a AND EXAMPLE 146b (R)-1-[2-(4,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone and (S)-1-[2-(4,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone (enantiomers of Example 32)

(RS)-1-[2-(4,6-Difluoro-1H-benzoimidazol-2-ylmethyl)-piperidin-1-yl]-1-[5-(4-fluoro-phenyl)-2-methyl-thiazol-4-yl]-methanone, E32 was separated to give the title compounds (stereochemistry not assigned) using the following procedures:

Analytical separation: 10 uL of diluted sample (compound in methanol) was separated on a 4.6×250 mm, 10 micron, analytical ChiralCel OD column. A Berger Analytical SFC (Super Critical Fluid) instrument was used with system parameters as follows: mobile phase=90% CO2: 10% organic modifier, organic modifier=90% methanol: 10% chloroform v/v, 3000 psi, 2 mL/min, 40 C λ=254 nm

The enantiomers eluted at 6.4 min. and 8.1 min.

Preparative separation: Scale-up was preformed on a Prochrom Super C.20 instrument. The instrument parameters were as follows: 40 C, 21 MPa, 40 g/min CO2+4.5 ml/min organic modifier (as above), λ=300 nm, ChiralCel OD 20×250 mm, 10 micron column. 30 mg of racemate was introduced per cycle. Sample concentration=875 mg/13 ml solvent (sample solvent=5 ml chloroform and 8 mL methanol). Cycle time (run time)=17 minutes. The enantiomers eluted at 10.2 and 13.6 min. Elution times measured at peak maxima.

It is understood that the present invention covers all combinations of particular and preferred groups described herein above.

Determination of Orexin-1 Receptor Antagonist Activity

The orexin-1 receptor antagonist activity of the compounds of formula (I) was determined in accordance with the following experimental method.

Experimental Method

CHO-DG44 cells expressing the human orexin-1 receptor were grown in cell medium (MEM medium with Earl's salts) containing 2 mM L-Glutamine, 0.4 mg/mL G418 Sulphate from GIBCO BRL and 10% heat inactivated fetal calf serum from Gibco BRL. The cells were seeded at 20,000 cells/100 μl/well into 96-well black clear bottom sterile plates from Costar which had been pre-coated with 10 μg/well of poly-L-lysine from SIGMA. The seeded plates were incubated overnight at 37 C in 5% CO₂.

Agonists were prepared as 1 mM stocks in water:DMSO (1:1). EC50 values (the concentration required to produce 50% maximal response) were estimated using 11× half log unit dilutions (Biomek 2000, Beckman) in Tyrode's buffer containing probenecid (10 mM HEPES with 145 mM NaCl, 10 mM glucose, 2.5 mM KCl, 1.5 mM CaCl₂, 1.2 mM MgCl₂ and 2.5 mM probenecid; pH7.4). Antagonists were prepared as 10 mM stocks in DMSO (100%). Antagonist IC50 values (the concentration of compound needed to inhibit 50% of the agonist response) were determined against 3.0 nM human orexin-A using 11× half log unit dilutions in Tyrode's buffer containing 10% DMSO and probenecid.

On the day of assay 50 μL of cell medium containing probenecid (Sigma) and Fluo3AM (Texas Fluorescence Laboratories) was added (Quadra, Tomtec) to each well to give final concentrations of 2.5 mM and 4 μM, respectively. The 96-well plates were incubated for 60 min at 37 C in 5% CO2. The loading solution containing dye was then aspirated and cells were washed with 4×150 μL Tyrode's buffer containing probenecid and 0.1% gelatin (Denley Cell Wash). The volume of buffer left in each well was 125 μl. Antagonist or buffer (25 μL) was added (Quadra) the cell plates gently shaken and incubated at 37 C in 5% CO₂ for 30 minutes. Cell plates were then transferred to the Fluorescent Imaging Plate Reader (FLIPR, Molecular Devices) instrument. Prior to drug addition a single image of the cell plate was taken (signal test), to evaluate dye loading consistency. The run protocol used 60 images taken at 1 second intervals followed by a further 24 images at 5 second intervals. Agonists were added (by the FLIPR) after 20 seconds (during continuous reading). From each well, peak fluorescence was determined over the whole assay period and the mean of readings 1-19 inclusive was subtracted from this FIGURE. The peak increase in fluorescence was plotted against compound concentration and iteratively curve fitted using a four parameter logistic fit (as described by Bowen and Jerman, TiPS, 1995, 16, 413-417) to generate a concentration effect value. Antagonist Kb values were calculated using the equation:

Kb=IC50/(1+([3/EC50])

where EC50 was the potency of human orexin-A determined in the assay (in nM terms) and IC50 is expressed in molar terms.

Compounds of Examples tested according to this method had pKb values >7.0 to 9.4 at the human cloned orexin-1 receptor.

The orexin-2 receptor antagonist activity of the compounds of formula (I) was determined in accordance with the following experimental method.

Experimental Method

CHO-DG44 cells expressing the human orexin-2 receptor were grown in cell medium (MEM medium with Earl's salts) containing 2 mM L-Glutamine, 0.4 mg/mL G418 Sulphate from GIBCO BRL and 10% heat inactivated fetal calf serum from Gibco BRL. The cells were seeded at 20,000 cells/100 μl/well into 96-well black clear bottom sterile plates from Costar which had been pre-coated with 10 μg/well of poly-L-lysine from SIGMA. The seeded plates were incubated overnight at 37 C in 5% CO₂.

Agonists were prepared as 1 mM stocks in water:DMSO (1:1). EC50 values (the concentration required to produce 50% maximal response) were estimated using 11× half log unit dilutions (Biomek 2000, Beckman) in Tyrode's buffer containing probenecid (10 mM HEPES with 145 mM NaCl, 10 mM glucose, 2.5 mM KCl, 1.5 mM CaCl₂, 1.2 mM MgCl₂ and 2.5 mM probenecid; pH7.4). Antagonists were prepared as 10 mM stocks in DMSO (100%). Antagonist IC50 values (the concentration of compound needed to inhibit 50% of the agonist response) were determined against 10.0 nM human orexin-A using 11× half log unit dilutions in Tyrode's buffer containing 10% DMSO and probenecid.

On the day of assay 50 μL of cell medium containing probenecid (Sigma) and Fluo3AM (Texas Fluorescence Laboratories) was added (Quadra, Tomtec) to each well to give final concentrations of 2.5 mM and 4 μM, respectively. The 96-well plates were incubated for 60 min at 37 C in 5% CO₂. The loading solution containing dye was then aspirated and cells were washed with 4×150 μL Tyrode's buffer containing probenecid and 0.1% gelatin (Denley Cell Wash). The volume of buffer left in each well was 125 μl. Antagonist or buffer (25 μL) was added (Quadra) the cell plates gently shaken and incubated at 37 C in 5% CO₂ for 30 min. Cell plates were then transferred to the Fluorescent Imaging Plate Reader (FLIPR, Molecular Devices) instrument. Prior to drug addition a single image of the cell plate was taken (signal test), to evaluate dye loading consistency. The run protocol used 60 images taken at 1 second intervals followed by a further 24 images at 5 second intervals. Agonists were added (by the FLIPR) after 20 sec (during continuous reading). From each well, peak fluorescence was determined over the whole assay period and the mean of readings 1-19 inclusive was subtracted from this FIGURE. The peak increase in fluorescence was plotted against compound concentration and iteratively curve fitted using a four parameter logistic fit (as described by Bowen and Jerman, TiPS, 1995, 16, 413-417) to generate a concentration effect value. Antagonist Kb values were calculated using the equation:

Kb=IC50/(1+([3/EC50])

where EC50 was the potency of human orexin-A determined in the assay (in nM terms) and IC50 is expressed in molar terms.

Compounds of Examples tested according to this method had pKb values in the range 6.5-8.4 at the human cloned orexin-2 receptor.

The application of which this description and claims forms part may be used as a basis for priority in respect of any subsequent application. The claims of such subsequent application may be directed to any feature or combination of features described herein. They may take the form of product, composition, process, or use claims and may include, by way of example and without limitation the following claims: 

1. A compound of formula (I):

wherein: X represents CH₂; Y represents CO; Het is an optionally substituted bicyclic heteroaryl group selected from benzofuranyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, indolyl, and benzothienyl; Ar² represents an optionally substituted phenyl or a 5- or 6-membered heterocyclyl group containing up to 3 heteroatoms selected from N, O and S, wherein the phenyl or heterocyclyl group is substituted by R¹ and further optional substituents; or Ar² represents an optionally substituted bicyclic aromatic or bicyclic heteroaromatic group containing up to 3 heteroatoms selected from N, O and S; wherein said 5- or 6-membered heterocyclyl group is a pyridinyl, thiazolyl, pyrazolyl, pyridazinyl, thienyl, triazolyl or isoxazolyl group, and said bicyclic aromatic or bicyclic heteroaromatic group is a naphthyl, benzoxazinyl, quinolinyl, or isoquinolinyl group; R¹ represents hydrogen, optionally substituted(C₁₋₄)alkoxy, halo, cyano, optionally substituted(C₁₋₆)alkyl, optionally substituted phenyl, or an optionally substituted 5- or 6-membered heterocyclyl group containing up to 4 heteroatoms selected from N, O and S; R³ represents hydrogen or an optionally substituent (C₁₋₄)alkyl other than when Het is indolyl where R³ represents hydrogen or (C₁₋₄) alkyl; or a pharmaceutically acceptable salt thereof; with the proviso that the compound is not (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(1H-indol-3-ylmethyl)piperazine, (2R)-1-(3,5-dichlorobenzoyl)-2-[(1H-indol-3-yl)methyl]piperazine, (2R)-2-[1H-indol-3-yl)methyl]-1-[3-methoxy-5-trifluoromethyl)benzoyl]piperazine; or 1-benzoyl-2-[1H-indol-3-yl)methyl]piperazine.
 2. A compound according to claim 1 wherein R¹ represents optionally substituted phenyl, pyridinyl, pyrazolyl, pyrimidinyl or oxadiazolyl group.
 3. A compound according to claim 1 wherein R¹ represents optionally substituted phenyl group.
 4. A compound according to claim 1 wherein Ar² represents an optionally substituted phenyl, pyridinyl, thiazolyl, pyrazolyl, thienyl, triazolyl, quinolinyl, or isoquinolinyl group.
 5. A compound according to claim 1 wherein Ar² represents an optionally substituted phenyl, pyridinyl, thiazolyl, pyrazolyl, thienyl, or 1,2,3-triazolyl group.
 6. A compound according to claim 1 wherein Ar² is optionally substituted by (C₁₋₄)alkyl, hydroxy(C₁₋₄)alkyl, R^(a)R^(b)N, (C₁₋₄)alkoxy, R^(a)R^(b)N(CH₂)n, (C₁₋₄)acyl, and (C₁₋₄)alkylamido.
 7. A compound according to claim 1 wherein Het is benzimidazolyl, benzofuranyl or benzoxazolyl.
 8. A pharmaceutical composition comprising the compound according to claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.
 9. A method of treating a disease or disorder where an antagonist of a human orexin receptor is required, which comprises administering to a subject in need thereof an effective amount of the compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein said disease or disorder is selected from obesity and obesity associated with Type II diabetes.
 10. A method of treating insomnia, which comprises administering to a subject in need thereof an effective amount of the compound according to claim 1, or a pharmaceutically acceptable salt thereof
 11. A method of treating or preventing diseases or disorders where an antagonist of a human orexin receptor is required, which comprises administering to a subject in need thereof an effective amount of a compound selected from (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(1H-indol-3-ylmethyl)piperazine, (2R)-1-(3,5-dichlorobenzoyl)-2-[(1H-indol-3-yl)methyl]piperazine, (2R)-2-[1H-indol-3-yl)methyl]-1-[3-methoxy-5-trifluoromethyl)benzoyl]piperazine; or 1-benzolyl-2-[1H-indol-3-yl)methyl]piperazine, wherein said disease or disorder is selected from insomnia, obesity and obesity associated with Type II diabetes. 